'Pied Piper' was the British programme to evacuate children from cities to the country or even overseas in the face of the threat of German bombing (1939/44).

During the 1930s the threat of bombing from the air had become a huge spectre in the minds of the government and the public as a result of the well publicised claims of air theorists such as Marshal of the RAF Sir Hugh Trenchard and Generale Giulio Douhet that air bombardment would be the decisive weapon of future wars, and that the bomber 'would always get through'. These hypothetical claims were then, it seemed, borne out by events such as the German 'Rügen' bombing of Guernica in the Spanish Civil War (1936/39).

The fear that major cities would be utterly destroyed in war led the British government to plan for the evacuation of civilians from probable targets. The British Air Raid Precautions Committee of 1924 evaluated what might happen in a future war, but with hindsight some of its casualty predictions were altogether too high. Yet the anticipated civilian casualty rate increased steadily throughout the 1930s. The Air Raid Precautions service was activated on 25 September 1938, and a start was made on preparations to cope with air raids on major civilian targets: many buildings had their basements requisitioned for adaptation as air raid shelters, numerous slit trenches were dug in public parks, 50 barrage balloons rose over London, and almost 40 million gas masks were distributed.

A number of nervous people, their natural fears worsened by the fears of the time, took further measures and sought refuge in more rural areas.

On 29 September 1938, the British government announced plans to evacuate some 2 million persons from London in the event of war. Based on the pre-war reports, this plan was seen as necessary to reduce demoralisation and control the 'inevitable' panic. The plan had been developed in the summer of 1938 by the Anderson Committee.

The country was divided into zones, classified as 'evacuation', 'neutral' or 'reception', and the scheme ordained that priority evacuees were to be moved from the major urban centres and billeted on the available private housing in more rural counties. Each area covered roughly a third of the population, although a number of urban areas later bombed were not classified for evacuation. Early in 1939, the reception areas compiled lists of available housing, space for 4.8 million people being found, and the government also constructed camps with spaces for a few thousand more people.

Early in the summer of 1939, the government began publicising its plan through local authorities. The government had overestimated demand: only 50 rather than the anticipated 80% of school-age children were moved from urban areas. There was also an enormous regional variation: towns in Yorkshire evacuated less than 15% of their children, while more than 60% of children were evacuated from Liverpool and Manchester. The refusal of the central government to spend large sums on preparation also exercised a serious dampening of the effectiveness of the plan.

There was a steady flow of evacuation from June 1939, although official evacuation began only on 1 September, two days before the UK declared war on Germany. In London and other large cities priority evacuees boarded trains for removal to rural towns and villages in the designated reception areas. Given the uncertainty of registering for evacuation, the movement was also disjointed: evacuees were gathered into groups and put on the first available train, regardless of its destination. School and family groups were further separated in the transfer from mainline trains to more local transport. Accordingly, some reception areas became overwhelmed. East Anglian ports received many children from Dagenham evacuated by paddle steamer. Some reception areas received more than the expected number of evacuees and others found themselves receiving 'wrong' people, i.e. evacuees from a priority group/social class different from their preparations.

Almost 3.75 million people were moved, and about one-third of the entire population experienced at least some of the effects of the evacuation.

In the first three days of official evacuation, almost 1.5 million people were moved: 800,000 school-age children, 500,000 mothers and young children, 12,000 pregnant women, 7,000 disabled persons, and over 100,000 teachers and other 'helpers'. The initial move was undertaken in quite high spirits and there were no serious accidents. Another 2 million or so more affluent individuals evacuated privately, settling in hotels for the duration, although several thousands took themselves farther afield to Canada, the USA, South Africa, Australia, and the Caribbean islands.

The government also undertook measures to save itself: in 'Plan Yellow' some 23,000 civil servants and their paperwork were despatched to available hotels in the better coastal resorts and spa towns. In preparation for the expected destruction of London, other hotels were requisitioned and emptied for any 'Black Move', the government’s departure from the capital.

Other prominent groups were also evacuated. Art treasures were sent to distant storage, the National Gallery’s collection spending the war at a quarry in North Wales, for instance. The Bank of England descended on the small town of Overton. The BBC moved variety production to Bristol and senior staff to a manor near Evesham. A number of the larger British companies also moved their head offices or their most vital records to comparative safety away from the capital.

Another evacuation effort was started during the fall of France. During the 13/18 June 1940 period some 100,000 children were evacuated or, in many case, re-evacuated. Efforts were made to remove the vulnerable from coastal towns in southern and eastern England facing German controlled areas. By July more than 200,000 children had been moved, and some towns in Kent and East Anglia had suffered a 40% drop in population. The evacuation process was then further complicated by the influx of 30,000 European refugees and, on 20/24 June, 25,000 people from the Channel Islands group.

Men of German and, later, Italian origin were interned from 12 May 1940, and an unpalatable truth was that many of these interned persons were refugees from the tyranny of Adolf Hitler. By July, almost all of these men under 70 were held in military camps, mainly on the Isle of Man.

In May 1940 the Children’s Overseas Reception Board (CORB) was created to organise the evacuation of children to the dominions. A surprising 210,000 applications had been made by July, when the scheme closed. However, shipping shortages quickly slowed the evacuation to a crawl. After the sinking of the City of Benares on 17 September, the entire plan was scrapped after only 2,664 children had been sent aboard. About 13,000 children had been privately evacuated overseas.

When the Blitz began in September 1940, there were clear grounds for evacuation. Chastened by the earlier efforts, the government did not seek compulsory evacuation: free travel and billeting allowance were offered to those who made private arrangements. They were also given to children, the elderly, the disabled, pregnant women, the ill, or those who had lost their homes (some 250,000 in the first six weeks in London). By the combination of all the state and private efforts, London’s population was reduced by a little less than 25%. As bombing encompassed more towns, 'assisted private evacuation' was extended. London proved resilient to bombing despite the heavy bombardment it suffered. The destruction in the smaller towns was more likely to provoke panic and spontaneous evacuations.

The number of official evacuees rose to a peak of 1.37 million by February 1941, and by September at slightly more than 1 million. By the end of 1943, there were just 350,000 people officially billeted. However, the start of V-1 flying bomb attacks in June 1944 provoked a significant exodus from London. Up to 1.5 million people had left by September, but only 20% of these were 'official' evacuees. From September 1944, the evacuation process was officially halted and reversed for most areas except London and the east coast.

Returning to London was not officially approved until June 1945. In March 1946 the billeting scheme was ended, with 38,000 people still without homes.