The three million children who were evacuated during the war are now elderly people, and few of them have spoken publicly about their experiences. In those days you were expected to shut up and ‘get on with it’, and there was little interest in the psychological effect on them or on their mothers, who had to let them go for their own sake.

Most evacuees went to quiet parts of Britain and were billeted with anyone who would take them “in scenes that would make modern child protection professionals blanch”.

Some parents, including a group from Oxford, felt that they could not risk their children growing up under Nazism and shipped them to North America. This was stopped when the City of Benares was torpedoed and 77 children died.

Yet there is no doubt that evacuation saved countless thousands of lives. It was also a positive experience for about 85 per cent of the children, particularly the older ones who could understand what was happening.

Julie Summers, a distinguished Oxford social historian, has interviewed several survivors whose stories are told here for the first time.

Their reactions range from”it ruined my life” to “it had been such a wonderful experience for me. . . and it made me determined to make something of myself”.

There were all kinds of human dramas and sometimes tragedies. Novels like Michelle Magorian’s Back Home, Noel Streatfeild’s Saplings and Barbara Noble’s Doreen show a little of what went on in the evacuees’ minds.

Working-class children went to middle-class homes and found when they returned that they had little in common with their parents. Many became deeply attached to their foster families and kept up the connection for as long as they lived. A few were used as free labour or abused.

I found this book deeply affecting. It gives us the facts and figures, but it also makes us think about the long-term effect of war on children, even those who, unlike children elsewhere, were protected from the Blitz.

Julie Summers will discuss her research at the Oxford Literary Festival on April 5. She will also appear on April 4 with fellow author Kitty Dimbleby to chair a discussion of The Daffodil Girls, an account of the experiences of Army wives.

See www.oxfordliteraryfestival.com, box office 0870 343 1001.