Spanning five years, eight months, and five days, the Battle of the Atlantic was the longest military campaign of the Second World War, lasting from the outbreak of war on 3 September 1939 until the German surrender on 8 May 1945. So vital was this campaign to Britain's war effort and home front morale that wartime British Prime Minister Winston Churchill claimed that the '[t]he only thing that ever really frightened me during the war was the U-boat peril.' While the Battle of the Atlantic was an Allied effort spanning the ocean between Europe and North America and principally involving the naval and air forces of the United Kingdom, Canada, and the United States, command of the battle in the eastern Atlantic was exercised by the Royal Navy's Commander, Western Approaches. Established in 1939 and originally based in the southwestern port of Plymouth, the Western Approaches Combined Headquarters moved to Derby House in Liverpool in February 1941 following the decision to re-route Allied transatlantic convoys around the north of Ireland in response to the threat posed by German U-boats and aircraft. From then until its closure on 15 August 1945, Western Approaches Command was responsible for ensuring the safety of inbound and outbound Allied merchant shipping in the waters around the UK and prosecuting the war against German U-boats, surface vessels, and aircraft through its operational command of convoy escort groups and naval and air assets. Escort and anti-submarine forces allocated to Western Approaches Command were based in Liverpool, Greenock, Londonderry, and Belfast. Although three Royal Navy admirals held the title of Commander, Western Approaches, the most famous of them was the longest-serving, Admiral Sir Max Horton, who held command from 19 November 1942 until the end of the war.
With the Germans and Japanese defeated, Western Approaches Command was disbanded and the Combined Headquarters was largely stripped of equipment and sealed up. While the rest of Derby House was later converted into modern offices, renovation of the reinforced concrete bunker in the building's basement was deemed impractical. After decades of neglect and deterioration, the bunker was restored to its wartime appearance and, in 1993, opened to the public as the Western Approaches Museum. In 2017, the museum was taken over by Big Heritage, a social enterprise group, which has invested in significant restoration work, including the opening of several parts of the Combined Headquarters bunker sealed since the 1960s.
Below: The front and reverse sides of the admission ticket at the Western Approaches Museum. The ticket is a reproduction of the wartime day pass issued to visitors to secure government and military installations, outlining the conditions of entry. The four circles on the reverse side of the ticket are for stamps that today's visitors can add at designated stations throughout the museum.
With the Germans and Japanese defeated, Western Approaches Command was disbanded and the Combined Headquarters was largely stripped of equipment and sealed up. While the rest of Derby House was later converted into modern offices, renovation of the reinforced concrete bunker in the building's basement was deemed impractical. After decades of neglect and deterioration, the bunker was restored to its wartime appearance and, in 1993, opened to the public as the Western Approaches Museum. In 2017, the museum was taken over by Big Heritage, a social enterprise group, which has invested in significant restoration work, including the opening of several parts of the Combined Headquarters bunker sealed since the 1960s.
Photos taken 31 October 2024
 |
| The Western Approaches Museum is located in Derby House, at the corner of Rumford Street and Chapel Street. |
 |
| The entrance to the Western Approaches Museum. |
 |
| After collecting their admission ticket at the front desk, visitors descend a flight of concrete steps into the basement level complex of rooms comprising the former Western Approaches Command Combined Headquarters. |
 |
| The first stop on the self-guided tour route is a small theatre playing a looped introductory film about the role and work of Western Approaches Command during the Second World War. |
 |
| The next room is Dock Lane, a recreation of a typical wartime street in Liverpool, complete with shopfronts and streetlamps festooned with patriotic Union Jack bunting. This room and the next one seek to establish the context of wartime Britain. |
 |
| The fictional Parker's confectionery shop features strips of tape over the glass in the window and door, a measure adopted by business and home owners against the effects of blast from German bombs. |
 |
| The interior of Parker's confectionery shop, with boxes and glass jars of rationed sweets, as well as newspapers and magazines. |
 |
| The J.A. Dempsey green grocer. A wooden hutch contains replica carrots, cabbages, cauliflowers, potatoes, and onions, popular wartime staple vegetables that could be grown by homeowners in Britain to supplement heavily rationed diets. |
 |
| The interior of the J.A. Dempsey grocer's shop features shelves stocked with limited quantities of packaged wartime food, including tins of dried coffee, vegetables, soup, salmon, beef suet, bacon, jam, and boxes of tea, sugar, and soap. |
 |
| A wartime propaganda poster produced by the Ministry of Food, encouraging Britons to make potato soup and to feed vitamin A-rich carrots to children. |
 |
| The other side of the Dock Lane recreation contains an ice cream shop whose owners have closed their business during the war and, next door, a boarded-up bomb-damaged building. |
 |
| The next stop on the tour route is a reproduction of a recruiting fair set up in a community centre, complete with tables for each of the armed services (Royal Navy, Army, Royal Air Force, Royal Marines and associated women's auxiliary services) and a recruitment film. After the declaration of war against Germany in September 1939, the UK government enacted the National Service (Armed Forces) Act, requiring all men between the ages of 18 and 41 living in the UK to join the armed forces. A second National Service Act, passed by Parliament in December 1941, widened the scope of conscription, making all unmarried women and childless widows between 20 and 30 years of age liable for service. Additionally, this new legislation required all men up to age 60 to undertake National Service, including military service for men under 51. This expansion of National Service was designed in part to ensure sufficient men for police and civil defence organisations and women for the auxiliary units of the armed forces. Mandatory registration for National Service continued throughout the war, though many Britons volunteered for service with the armed forces without waiting for their National Service call-up notices to arrive. |
 |
| Moving from the displays on wartime Britain, visitors proceed into the rooms of the former Western Approaches Combined Headquarters, beginning with the Teleprinter Room. During the war, this space housed the Royal Air Force's Wireless Telegraphy Office, equipped with radios for transmitting typed messages. Today, it contains the teleprinters originally installed in the adjacent room. Over 30 million messages were sent and received by the Western Approaches Combined Headquarters during the Second World War. |
 |
| To send a message via a teleprinter, an operator typed messages on the keyboard of her machine, with each keystroke sending an electrical pulse down the phone line via a transmission system. At the destination, a receiving teleprinter decoded the pulses and printed the message on paper. The women teleprinter operators, members of the Royal Corps of Signals, did not know the contents of the messages they sent and received, as the messages were encoded. When typing messages for transmission, the operators needed to be absolutely accurate to ensure that the groups of coded letters were not garbled by an error. The teleprinter operators worked a morning and afternoon shift, followed by an afternoon and night shift the next day, and with the third day off for rest. |
 |
| A narrow corridor leads from the Teleprinter Room to the Switchboard Room and Code Room on the right and the Operations Room on the left. |
 |
| The Switchboard Room. During the Second World War, this space housed the Royal Naval Signals Office. The navy's Signals Division was responsible for all telegraphy, signalling, signal books, codes, and ciphers. It worked closely with the Royal Naval Receiving Room, located in an adjacent room. Today, this room houses the switchboards that were used to receive all audio communications in the Western Approaches Combined Headquarters building. |
 |
| Upon being alerted that there was a message to transmit, the switchboard operators would plug in the appropriate machine or connect the jack plug to the appropriate outgoing socket to establish the phone connection. |
 |
| The Royal Naval Central Receiving Room, also known as the Code Room. The shifts of men and women posted to the Code Room 24 hours a day listened for Morse code messages and translated each message into encoded blocks of text (ciphers). The enciphered text would then be passed to the cipher decoding offices to be deciphered into plain English. The Royal Naval Central Communications Office would determine the appropriate recipient in the building and deliver the deciphered text accordingly. This whole process, from receipt of the Morse code message to delivery of the deciphered plain text, took approximately 15 minutes. |
 |
| The heart of the Western Approaches Combined Headquarters building was the two-storey Operations Room. It was here that intelligence information received by personnel in the various parts of the building came together to produce an accurate and ever-changing plot of convoy and anti-submarine operations in the North Atlantic and around the coasts of the United Kingdom. Although anti-submarine forces, both ships and aircraft, sought to hunt down and kill German U-boats, Britain's primary objective was to ensure the safe and timely arrival of merchant shipping to keep the nation fed and supplied with vital war materiel. |
 |
| The massive map occupying an entire wall of the room depicts the North Atlantic theatre of operations. The map was used to plot the locations of Allied convoys, Allied anti-submarine forces, and enemy forces. Decisions made in this room, such as the rerouting of a convoy's course or the deployment of an anti-submarine hunting group or maritime patrol aircraft, could determine the fate of thousands of Royal Navy and merchant sailors at sea. Ships, aircraft, and entire convoys were represented by pins on the map; when a ship was sunk, often with significant loss of life, an Operations Room plotter would remove the associated pin from the map to ensure an accurate reflection of the situation. |
 |
| This corner of the Operations Room contains boards with elaborate details on aircraft assigned to convoy escort and anti-submarine operations, including their squadron affiliations, bases, operational status, and estimated times of departure and arrival. Anti-submarine air support for the convoys was critical, with the introduction of long-range maritime patrol aircraft like the Liberator and Catalina, allowing Allied forces to close the mid-ocean air gap that the German U-boats had exploited to great effect during the war's early years. While Allied anti-submarine aircraft were able to swoop in on unsuspecting U-boats to deliver depth bombs, even the sighting of an Allied aircraft would force a U-boat to crash dive to avoid being attacked on the surface, thereby increasing the odds of the the U-boat losing contact with a convoy it was stalking. |
 |
| Separated from the Operations Room by large glass windows are the 'cabins' of the Royal Navy and Royal Air Force duty officers posted to the Operations Room. While Western Approaches Command was a Royal Navy formation, the Royal Air Force's No. 15 Group was co-located with it in Derby House and came under the operational command of Commander, Western Approaches. The naval and air duty officers in the Operations Room oversaw the work of the staff and logged all orders and signals, ensuring effective sea-air coordination of operations in Western Approaches Command's area of responsibility. In the autumn of 1940, Western Approaches Command established the concept of the 'escort group', comprising two to three destroyers and six corvettes which trained and operated together in defence of merchant convoys. By the autumn of 1941, escort groups of more specialised anti-submarine sloops and frigates were being formed. Given the steady growth of Allied forces, by 1943 'support groups' had been formed; these teams of highly-trained anti-submarine vessels were not tied to any particular convoy and could be deployed to reinforce the escort groups of convoys threatened by German U-boats and aircraft. By 1944, with more-capable anti-submarine frigates entering service with the established escort groups, many of the smaller Flower-class corvettes that had borne the burden of convoy defence in the early years of the war were allocated to a pool of escort vessels that could be called upon as required. |
 |
| The Royal Air Force Cabin was staffed by RAF officers overseeing the air component of the Operations Room's work. The RAF's No. 15 Group was responsible for flying patrols over the North Atlantic approaches to the UK in order to locate and attack enemy vessels and protect convoys of Allied merchant ships. Intelligence from aircraft flying in the North Atlantic was relayed to the bunker's radio room and plotted on the Operations Room maps. Using information displayed on the aircraft status boards in the Operations Room, the RAF Duty Officer could order aircraft to scramble from the nearest available airfield to intercept the enemy. |
 |
| Displayed in the RAF Cabin in the Operations Room are German maps of Liverpool and Birkenhead used by the Luftwaffe (German Air Force) to identify targets for air raids. As the principal British port for the transatlantic convoys bringing troops, war materiel, food, and fuel to sustain the British war effort, Liverpool was an important target for the Germans. The first German air raid on Birkenhead occurred on 9 August 1940 and, over the next 16 months, 3,899 people in Liverpool, Birkenhead, and the nearby towns of Bootle and Wallasey were killed by German bombs. |
 |
| The Second World War uniform of a Wing Commander in the Royal Air Force. An officer at the rank of Wing Commander served as the RAF Duty Commander in the Operations Room. |
 |
| The aircraft status boards are easily visible through the windows of the RAF Cabin. Based on the threat facing a convoy in the Western Approaches, the RAF Duty Commander and his subordinate officers in the cabin could call up RAF stations to order maritime patrol aircraft or long-range bombers to scramble in response. |
 |
| This speaking tube in the Royal Navy Cabin was connected directly to the Admiral's office upstairs. The tube, similar to those found on all Royal Navy and merchant ships, was used to quickly deliver urgent voice messages and orders. |
 |
| The Royal Navy Cabin overlooking the Operations Room. It was from here that the RN Duty Commander and subordinate naval officers maintained a watch over the naval aspects of proceedings being plotted on the Operations Room maps. The Royal Navy and Royal Air Force cabins worked closely together to ensure a coordinated approach to combined sea-air operations in the North Atlantic approaches to the UK. Telephone and radio communications to Royal Air Force stations and airfields, as well as other parts of the bunker, ensured that air assets could be called upon to support naval ships and merchant vessels at sea. |
 |
| The Second World War uniform of a Commander in the Royal Navy. A Commander would serve as the Duty Commander in the Operations Room's Royal Navy Cabin. This officer would oversee all messages arriving from ships, keep a log of all signals, orders, and other communications, and ensure the smooth running of the Operations Room. |
 |
| Desk trays in the Operations Room hold documents classified 'Most Secret', containing intelligence on German submarine and aircraft movements derived from decrypted radio signals or other sources. |
 |
| The Operations Room, showing the huge wall map of the North Atlantic on which convoys and Allied naval and air forces were plotted. Convoys followed one of two routes: a transatlantic route between the UK and North America and a southward route to West Africa and onward to the South Atlantic and Indian Ocean. Movable ladders allowed plotters, largely personnel of the Women's Royal Naval Service (WRNS) and Women's Auxiliary Air Force (WAAF), to move, add, or remove pins and flags representing ships, submarines, aircraft, and convoys based on intelligence received in the bunker. |
 |
| The layout of the Operations Room has been preserved as it was when the Western Approaches Combined Headquarters bunker was shuttered at the end of the war in August 1945. |
 |
| A gallery devoted to the Second World War Arctic convoys, sponsored in part by the Russian embassy in the United Kingdom and containing a number of artefacts from the Russian Arctic Convoy Project Museum. These displays occupy the original Convoy Plotting Room used to plan the Atlantic convoy routes. Separated from the main Operations Room, it was in the Convoy Plotting Room that Royal Navy and Women's Royal Naval Service personnel established sailing routes across the Atlantic and rerouted convoys threatened by German submarines, surface vessels, or aircraft. During the war, large table maps were laid out in this room and used to plot the convoy routes and account for all possibilities, based on intelligence received by Western Approaches Command. With the UK dependent on imports for 70% of its required food at the beginning of the war, the convoys were a critical lifeline to sustain Britain's war effort and morale. |
 |
| A display of items commemorating the Arctic convoys, including medals issued to convoy veterans by the Russian government to mark the 40th, 50th, 60th, and 70th anniversaries of the Great Patriotic War (the Russian name for the Second World War); a commemorative plate depicting Russian Navy commander General Fyodor Ushakov (1745-1817) awarded to convoy veterans to mark the 80th anniversary of the first Arctic convoy; a white beret worn by Arctic convoy veterans in the Russian Convoy Club; and an Arctic Star medal awarded by the British government for any operational service in the Arctic between 3 September 1939 and 8 May 1945. |
 |
| This White Ensign was presented to Captain John H Allison, commanding officer of the Z-class destroyer HMS Zephyr, which escorted Arctic convoys JW-66 and RA-66 to and from the Soviet Union in April 1945. The flag is on loan from the Russian Arctic Convoy Museum Project. |
 |
| A 1:72 scale model of HMS Bluebell, depicted sailing through frigid, ice-infested Arctic waters. Commissioned in 1940, Bluebell was one of 294 Flower-class corvettes built during the war. Between September 1942 and March 1943 and again between February and April 1944, Bluebell was assigned to Russian convoy service, escorting merchant ships in four separate convoys. After brief service supporting the D-Day landings in Normandy in June 1944, Bluebell was redeployed to the Arctic convoys. While preparing to escort convoy RA 64 returning to the UK from Murmansk, Bluebell was torpedoed by German submarine U-711 on 17 February 1944; the explosion caused the detonation of Bluebell's depth charges and the corvette sank in less than 30 seconds, with the loss of all but one of her crew of 86 officers and men. During four years of war, 78 convoys comprising a total of 1,400 merchant ships were sent to Russia, taking one to two weeks to make the 2,500 mile (4,023 kilometre) voyage under constant threat from German U-boats, aircraft, and surface vessels, as well as terrible weather. The merchant vessels in the Arctic convoys came from 13 different countries and were manned by sailors of more than 40 nationalities. |
 |
| The Power Corridor houses equipment used to supply electricity to the building and its approximately 300 personnel. Given the critical role of communications in the internal and external operations of Western Approaches Command, a reliable power supply was vital to guarantee the ability to send and receive messages. The electrical supply had to be able to withstand any outside bombing attacks, while providing sufficient heating, ventilation, and power to permit the staff to carry out their tasks quickly and efficiently. |
 |
| Ascending from the Basement Level to the Lower Ground Floor Level, visitors arrive at the entrance to the suite of rooms used by the Commander-in-Chief, Western Approaches and his Flag Lieutenant. |
 |
| Located at the top of the stairs on the Lower Ground Floor Level is one of the original wartime entrances to the Western Approaches Combined Headquarters. This door, set into reinforced concrete walls measuring three feet (0.9 metres) in thickness, provided a secure and discreet entrance for staff arriving at and departing from the building. The door leads out to the rear of the building rather than a street, ensuring added security and privacy. |
 |
| The security checkpoint just inside the wartime entrance. This checkpoint would have been manned by Royal Marine guards around the clock, with all visitors required to show identification. Royal Marines on duty at the entrances were always armed with a pistol, while those on guard duty outside Derby House were equipped with a standard Lee Enfield No. 4 rifle. The Royal Marine guards also had access to Thompson sub-machine guns and even a Vickers heavy machine gun in a reinforced post at the Rumford Street entrance to the building. |
 |
| Entering the suite of rooms used by the Commander-in-Chief of Western Approaches Command and his Flag Lieutenant, visitors first encounter the Flag Lieutenant's room. The room is equipped with bunk beds, a wash basin, and a telephone. During Admiral Max Horton's tenure as Commander-in-Chief, Western Approaches (November 1942 to August 1945), his Flag Lieutenant, Kay Hallaran, used this room. Hallaran, an officer in the Women's Royal Naval Service, was specially selected to serve as Horton's personal assistant. |
 |
| The Guardroom outside the Commander-in-Chief's suite. Visitors to see the Commander-in-Chief would check in here. The space has a telephone and a small stove and oven to prepare hot meals and drinks for the Admiral and his Flag Lieutenant. |
 |
| This small bedroom, with a window overlooking the Operations Room below, was where the Commander-in-Chief could rest during long periods on duty in the bunker. |
 |
| The office of the Commander-in-Chief, Western Approaches. This office, overlooking the Operations Room and its wall maps, was occupied by two men, in succession: Admiral Sir Percy Noble from February 1941 to November 1942 and Admiral Sir Max Horton from November 1942 to August 1945. Both men played critical roles in securing the Allied victory in the Battle of the Atlantic. Horton, the most famous Commander-in-Chief, Western Approaches, commanded the submarine HMS E9 during the First World War and was therefore a natural fit to coordinate Western Approaches' anti-submarine operations in the Second World War. Horton retired soon after the end of the war and died in 1951 at age 67. |
 |
| The Commander-in-Chief's office today displays information on the life and career of Admiral Sir Max Horton, as well as various mementos commemorating him, such as the bronze bust and Life magazine seen here. |
 |
| A spartan corridor leads onward from the Commander-in-Chief's suite. |
 |
| This Gaumont Kalee Dragon film projector was originally installed in London and used by Prime Minister Winston Churchill to view secret footage of wartime operations. Much of the Second World War was filmed to record documentary evidence of events, in part to show politicians in the UK what was occurring. Cameras on aircraft and carried by soldiers on the ground, as well as journalists embedded with Allied forces, recorded this operational footage. Although some footage was withheld from the public to avoid jeopardising operations or national morale, the Ministry of Information provided secret screenings of war footage to Churchill, some of which were considered too shocking to show to wider audiences. Ministry of Information newsreels of war footage deemed acceptable for public consumption were played in cinemas to show the progress of British and Allied forces; these newsreels massively increased the popularity of the cinemas. |
 |
| The uniform of a 3rd Officer of the Women's Royal Naval Service in 1943 is displayed in the bunker's former Battery Room. In the event of an electrical power failure, batteries were used to ensure the uninterrupted flow of messages to and from the bunker. The batteries were kept in separate rooms to provide proper ventilation and to isolate any fumes or corrosive chemicals. |
 |
| This room is devoted to the end of the war, with a television showing newsreel footage of Victory in Europe (VE) Day, 8 May 1945, and reproductions of newspapers available for visitors to read. Following Japan's surrender on 15 August 1945, the Western Approaches Combined Headquarters was no longer needed. Much of the bunker's contents were cleared out, the rooms sealed, and the doors closed for all military purposes. |
 |
| Given the significant number of women who worked in the Western Approaches Combined Headquarters during the war, it is fitting that it should today house a museum on the Women's Royal Naval Service, whose members were nicknamed 'Wrens'. The Wrens and their counterparts in the Women's Royal Air Force Auxiliary (WAAF) were responsible for carrying out many of the day-to-day operations within the Western Approaches Combined Headquarters, serving in a wide range of roles, including as plotters, coders, signal officers, and messengers. Their work was vital to the smooth functioning of the bunker. |
 |
| Part of the Wrens Museum within the Western Approaches Museum. The Women's Royal Naval Service was formed during the First World War to fill shortages and free up male naval personnel for service at sea. Disbanded in 1919, the Wrens were reestablished in 1939, with women aged between 17.5 and 43 years (50 if they had previously been a Wren) eligible to enlist. The force reached a peak strength of 74,000 in 1944, with Wrens serving in over 200 different jobs. The Women's Royal Naval Service was made a permanent service in February 1949, with 3,000 female personnel supporting the Royal Navy in administrative and ancillary roles. From 1977, the Wrens were brought under the Naval Discipline Act, thereby opening up many more naval trades to women and paving the way for the full integration of women into the Royal Navy. The Women's Royal Naval Service was disbanded as a separate service in 1993. |
 |
| A motorcycle used by Wren dispatch riders to deliver important messages between military and naval facilities in the UK during the Second World War. |
 |
| A recreation of a Wren's barracks room. During the two World Wars, Wrens were regularly accommodated in re-purposed buildings, including hotels, hostels, boarding houses, mansions, and holiday camps. Upon recruitment, Wrens were classed as either 'mobile' or 'non-mobile', with mobile Wrens willing to be posted anywhere, including the codebreaking centre at Bletchley Park, Portsmouth, Malta, Northwest Europe, or Western Approaches Command in Liverpool. Immobile Wrens worked locally and continued to live at home rather than in barracks. For those Wrens living in barracks, it was customary at the start of the war for 8-10 women to share a basic room with few amenities. Later, Wrens began to be housed in buildings with more space and amenities. Wrens were able to personalise their rooms with mementos from home as long as the rooms were kept clean and tidy. Wrens were always accommodated in separate buildings from male naval personnel, with male quarters off limits to Wrens and some Wrens' accommodation buildings even being surrounded by fencing. |
 |
| This bathtub is rumoured to have been used by Prime Minister Winston Churchill during his regular visits to the Western Approaches Combined Headquarters during the Second World War. Former Wrens have recalled hearing the sound of Churchill splashing around in the tub. |
 |
| The uniform of a Women's Royal Naval Reserve Chief Officer. Established as the Women's Royal Naval Volunteer Reserve in 1951, the organisation was formed so that a small number of women trained in certain specialisations could undertake operational duties throughout the United Kingdom during war or national emergency. Renamed as the Women's Royal Naval Reserve (WRNR) in 1958, the organisation came under the Naval Discipline Act in 1977 and thereby was fully integrated into the Royal Naval Reserve. WRNR members were concentrated in various branches, including Intelligence, Communications, and Plotting. Today, the Royal Naval Reserve, comprising both male and female members, numbers around 3,000 people who can be called upon in times of crisis. |
 |
| A WRNS tropical uniform issued to personnel posted to the Mediterranean, Africa, India, or the Far East. From January 1941, WRNS personnel could be drafted for overseas service. The shoulder straps and buttons are similar to those on the uniforms of male Royal Navy officers. The uniform on display belonged to Barbara McGregor, with the handmade dress dating from 1980 and the separate skirt, blouse, handbag, and shoes dating from 1983. |
 |
| A WRNS mess dress uniform from the 1960s. This semi-formal uniform was worn by officers and optionally by some senior enlisted personnel for certain ceremonies and celebrations on private occasions. The mess dress comprises a blue evening dress and bolero showing service and rank badge, black stockings, plain court shoes, and black or matching blue silk. The uniform on display belonged to WRNS Third Officer Sue Rayment, circa 1965. |
 |
| This gallery, made up to resemble the office of the Director of the Women's Royal Naval Service, contains profiles of the Service's Directors during the First and Second World Wars: Dame Katharine Furse (1917-1919) and Dame Vera Laughton-Mathews (1939-1946). The rank title of Director was given to the head of the WRNS until 1946, when the title changed to Commandant and, in 1951 to Chief Commandant. |
 |
| The General Post Office (GPO) Switch Room contains communications equipment that was operated and maintained by GPO staff during the war. Even if Derby House's main telephone exchange was knocked out, the GPO's equipment would ensure the uninterrupted flow of messages to and from the Western Approaches Combined Headquarters. |
 |
| An original sign and indicator from the GPO Switch Room. |
 |
| An original Enigma coding machine recovered from the wreck of German submarine U-534. Considered by Nazi Germany to be secure against compromise, the Enigma was used to encipher the most secret of messages. The Enigma scrambled the letters of a message in a seemingly random manner before the message was translated into Morse code and transmitted via radio. Depending on the level of classification of the message, operators could choose between three levels of Enigma code. U-534 carried two Enigma machines which could have been used to double encipher messages for even greater security. Although it is estimated that between 40,000 and 120,000 Enigma machines were manufactured, Enigma operators were instructed to destroy their machines to avoid them being captured by Allied forces; as such, it is believed that fewer than 300 Enigma machines still exist today. U-534 was sunk off Denmark by a Royal Air Force Bomber on 5 May 1945, salvaged in August 1993, and moved to Birkenhead (across the River Mersey from Liverpool) for display from February 2009 until 2020. Following completion of a new visitor centre, it is planned that U-534 will re-open to visitors in Birkenhead in 2026. |
 |
| Visitors pass an original building sign on their way out of the Western Approaches Museum. |