Much effort has gone into creating the right atmosphere. Visitors enter through a mock-up Thirties railway platform - with steam hissing from invisible trains - then move on to a section devoted to the evacuees' experience of life in the countryside, dominated by an enormous model pig clambering half-way out of its sty.
Next, to the sound of seagulls, slapping waves and ships' sirens, it's up a gangplank to learn of the "seavacuees" - the children who were shipped abroad - before finally moving on to displays which deal with the end of the war and its emotional aftermath.
Nowhere does the exhibition disguise the essential misery of evacuation. Photographs show infants sobbing on railway platforms, mothers gazing sorrowfully from behind railway barriers, and parents desperately embracing their children.
Several prominently-displayed quotations make it clear that selection on arrival was regularly made on anything other than sentimental grounds. "If you were a child with glasses or with spots you were always left till the end, " remembers one evacuee.
Nor was accommodation of guaranteed quality. "We slept on mattresses on filthy floors, food was very sparse and there were rat droppings everywhere," recalls another.
Of the hundreds of exhibits, easily the most absorbing are the many letters to and from children. Set among various mementoes of the time - board games, toys, school reports and diaries, these tell of parental anxieties and childish preoccupations, some amusing, others simply painful ("Mummy, Mrs and Miss H have started to make Frankie and I go to bed in the dark and our poor little Frankie is terrified. He has been a little tinker today and has been smacked round the head").
By far the most poignant letter, though, was written by the parents of nine-year-old Beryl Myatt, one of 79 passengers lost when the evacuee ship the City of Benares was sunk by an enemy submarine in September 1940. Anticipating her arrival in Canada, the letter talks of Beryl enjoying copies of Dandy and Sunny Stories sent on before. At the top of the page, an arrow points to a paw print from Chummy, Beryl's dog.
But such tragedies were rare. Most "seavacuees" gained safe passage to cushy billets - and most came from privileged backgrounds. Not so thousands of their land-locked compatriots, whose poor physical condition and unsanitary habits appalled many middle-class foster parents.
It was the first time many of the "submerged tenth", the parents and children of the urban underclass, had experienced anything other than grimy, tough living. Printed on the wall of the country section, one extract from a 1941 letter says it all: "They call this spring, Mum, and they have it down here every year."
* "Evacuees". The Imperial War Museum, London. March 14 - October 27. Tel: 0171 416 5313. Adults Pounds 4.50, children Pounds 2.25, students Pounds 4.50, pre-booked schools free