The United Kingdom took part in World War II from 3 September 1939 until 15 August 1945. At the beginning of the war in 1939, London was the largest city in the world, with 8.2 million inhabitants. It was the capital not just for the United Kingdom, but for the entire British Empire. London was central to the British war effort. It was the favourite target of the Luftwaffe (German Air Force) in 1940, and in 1944-45 the target of the V-1 cruise missile, the V-2 rocket, and the unsuccessful V-3 "London gun".

An estimated 18,688 civilians in London were killed during the war, 0.23% of the population. 1.5 million were made homeless. 3.5 million homes and of office space were destroyed or damaged.

Preparations As early as June 1935, Air Raid Precautions (ARP) schemes were being put into place across London. The rules and resources of such schemes varied from borough to borough. ARP officers were expected to co-ordinate firefighting teams, rescuers and building repair in preparation for bombing raids. In June 1938, the Women's Voluntary Service (WVS) was founded at 41 Tothill Street to help combat and protect against air raids. At night, London was put under "black-out" rules, intended to make it as difficult as possible for the city to be seen from the air at night. Light sources such as street lamps, car headlights, and even cigarettes were to be put out or covered. In September 1938, Londoners were asked to present themselves at a local assembly point to be issued with gas masks to protect against mustard gas attacks.

London was encircled with three rings of defence. The outermost ring linked suburbs such as Rickmansworth, Potters Bar, Epping Forest, Hounslow, Kingston-upon-Thames and Bromley; the middle ring ran through Enfield, Harrow, Wanstead and West Norwood; and the inner ring ran around the north bank of the Thames from the river Brent to the river Lea. The outer two rings were anti-tank lines involving trenches, pillboxes and roadblocks; and the innermost ring was manned by the army. Floodgates were installed on the London Underground system to prevent the river breaching the tunnels. Barrage balloons were floated above London's skyline, forcing bomber planes to fly at an altitude that made it difficult for them to aim accurately. Some boroughs ran exercises to train their citizens and civil defence in the event of air raids. A flat in Fitzmaurice Place in Mayfair was acquired amidst great secrecy as a bolt-hole for the royal family in the event that London was invaded. Plans were also drawn up for them to flee to Canada if necessary.

In preparation for expected bombing raids, museums and libraries sent important materials to safety in the countryside. Beginning in August 1939, the collections of the Natural History Museum were evacuated to various stately homes around the countryside. The museum was open intermittently through the war. Around 30,000 rare books and manuscripts were moved from the British Museum to the National Library of Wales, and later from there to a disused quarry in Wiltshire. The National Gallery removed all its paintings from the premises to various locations, mostly in Wales. Aldwych Station was used to store valuables from the British Museum and the Public Record Office, including the Parthenon Marbles. Westminster Abbey's treasures were moved out of the church, and its immovable tombs protected with 60,000 sandbags. All venomous animals in London Zoo were killed to prevent them harming the public should they escape, and some large animals such as pandas and elephants were transferred to other zoos.

The Royal Society for the Prevention of Cruelty to Animals (RSPCA) put down 400,000 pets in London in the first week of the war alone in order to save food.

At noon on 1 September 1939, television producers at the British Broadcasting Corporation (BBC) headquarters in Alexandra Palace were told that the facility was shutting down immediately. The BBC announced that they would only be broadcasting radio on a single channel.

Evacuation On 28 September 1938, the London County Council (LCC) began to evacuate the first children from London to places in the country which were thought to be safer. The first contingent was made up of 1,200 nursery-school children and 3,100 physically disabled children. However, as a year passed without war materialising, plans to evacuate further children were cancelled.

On 1 September 1939, two days before the outbreak of war, the evacuation programme was re-started in earnest. Most of the evacuees left London by rail, although some along the riverside, particularly in Dagenham, left by boat, and more affluent families escorted their children in cars.

Fewer than half of all London parents took advantage of the scheme. When the children reached the countryside, their collection was sporadically organised, with some siblings being split up, and children paired with unsuitable guardians. There was no bombing in 1939, and most of the evacuees soon returned.Niko Gartner, "Administering'Operation Pied Piper'-how the London County Council prepared for the evacuation of its schoolchildren 1938-1939." Journal of Educational Administration & History 42#1 (2010): 17-32. By mid-October, an estimated 50,000 mothers and children were back in London. However, for those children who remained in or returned to London, schools were often closed and teachers evacuated with the rest of the class: by 11 January 1940, only 15 schools were open in the LCC area.

Not only were children evacuated from London- London hospitals evacuated their patients, and the government evacuated thousands of civil servants under the codename "Plan Yellow". Many civilians also moved out of London of their own accord at the beginning of the war, and by March 1940, the population of Chelsea had fallen from 57,000 to 36,000.

Food and rationing

In the first few months of the war, prices of essential goods spiked, with price controls being introduced in November 1939. Shopkeepers who were thought to be war profiteering by unduly raising their prices were liable to cause public outcry, or even to have their premises picketed by the Stepney Tenants' Defence League in the East End. Rationing rules were introduced throughout the war, beginning with petrol in September 1939, and expanding to cover food and clothing. When rumours spread about new rationing rules, some Londoners engaged in panic-buying before the restrictions were introduced- for example, writer Rose Macaulay witnessed "cars queueing up for miles round each garage to fill up" before petrol rationing was introduced. With petrol hard to come by, London's roads became deserted, with even buses and taxis being taken out of service.

Wealthy people could avoid the rules on rationing by eating at restaurants: for example, in May 1942, the war correspondent James Lansdale Hodson had smoked salmon, mushroom pâte, chicken, pudding, a cocktail and red wine at The Berkeley, writing "It's clear to me that if you have the brass [...] you can live in London very well." Later that month, restaurants were forbidden from charging more than five shillings for a meal in order to curb extravagance. Many restaurants reduced the size and luxuriousness of their dishes. The American Brigadier-General Raymond E. Lee noted that in London "one gets only a lump of sugar and a thin little flake of butter. No more iced cakes. Fewer kinds of cheese. Only six pages in the newspaper. All paper is saved." London County Council also opened "British Restaurants" in places such as Fishmongers' Hall, the Royal Veterinary College, and Gloucester House, which provided cheap, nourishing food in comfortable surroundings.

As well as some foodstuffs being rationed, some were impossible to get altogether. In April 1940, Lord Woolton announced that bananas would not return to London's grocers until after the war. One St John's Wood resident, Rosemary Black, was left the following note by her maid: "Madam, there is no honey, no sultanas, currants or raisings, no mixed fruits, no saccarine at present, no spaghetti, no sage, no herrings, kippers or sprats (smoked or plain), no matches at present, no kindling wood, no fat or dripping, no tins of celery, tomato or salmon. I have bought three pounds of parsnips." Spirits were difficult to come by and subject to price controls when they did appear. Some Londoners took to illegally distilling their own "hooch" instead, which could cause methyl poisoning. Feeding pets with food fit for human consumption was banned by the government, to the effect that even dog food became hard to come by. The public were encouraged to try new foods that were easier to get: the Naval and Military Club served catfish; horse was served in the House of Commons, and rook pie at the Grosvenor House Hotel. Some Londoners took up gardening in order to increase their access to vegetables, and public parks were turned into allotments to facilitate this. It was estimated that the parks of Croydon alone produced 15,000 meals a day. Tomatoes were grown in the window-boxes of Chatham House; the forecourt of the British Museum had peas, beans, onions and lettuces; and the roof of New Zealand House had three beehives. Many Londoners kept chickens or subscribed to pig clubs, and a flock of sheep were kept in Kensington Gardens.

Some Londoners considered it a point of pride to strictly follow rationing, but others illegally bought rationed goods from the black market. One Italian restaurant in Jermyn Street served steaks concealed under a huge pile of spinach. One civil servant called Mary Davies was served a black-market haggis by a friend, and wrote that "My sort of level wouldn't have done any black marketing [...] We would have considered that not really the done thing." There was also a "grey market" involving giving rationed goods as gifts- for example, the Walworth reverend J. G. Markham was offered a box of prunes by one of his parishioners. A common misconception among Londoners was that Jewish people were particularly strongly involved in or profiteering from the black market, but when the Royal Statistical Society studied the matter, they found that only three out of 50 convicted black marketeers were Jewish.

Food wastage was severely frowned-upon. Some Londoners were prosecuted for feeding bread to birds at Hyde Park, and Vere Hodgson was reprimanded by Kensington Salvage Council for throwing away mouldy bread. Wandsworth Council delivered cooking lessons on how to make cakes without fat or sugar, or make a family-sized bean cutlet for fourpence.

Londoners were encouraged to save paper in large quantities. Newspapers reduced to four or six pages long. In June 1943, Londoners donated their old books for salvage, recycling a grand total of 5.5 million books.

Bombing Prior to September 1939, it was widely-known in Britain that in the event of war in Europe, London would be the target of a bombing campaign. The Air Ministry predicted casualty rates of 18,750 per week in the capital, and the Mental Health Emergency Committee predicted that 3-4 million people would develop mental health problems such as hysteria. Mass graves were dug in North Sheen Cemetery to accommodate the expected thousands of dead each night.

At the beginning of the war, German dictator Adolf Hitler ordered that London was not to be attacked. However, on 24/25 August 1940, several bombs were dropped on London. Whether this was due to a change of heart on the part of Germany or due to an error on the part of the aircrew is debated, but British prime minister Winston Churchill ordered retaliatory attacks on Berlin in response.

The heaviest-hit areas of London during the war were the City of London, Holborn, and Stepney, each receiving over 600 bombs per , followed by Bermondsey, Deptford, Southwark, and Westminster.

The Blitz