Here’s a side of wartime Britain you don’t often hear about: in 1944 a group of teenage boys in Wales broke into an army depot and made off with guns and ammunition. They amused themselves shooting chickens in the hills until the Royal Marines came to get their guns back, when they held them at bay until their ammunition ran short. The boys were escorted home to a heroes’ welcome from their peers, and a week’s sentence in an approved school from a court martial.

When Robert Westall, author of The Machine Gunners, spotted the story in a newspaper clipping he naturally sought to find out more, but he found that the incident still seals lips in the area round Barmouth where it happened. However, it did set him off gathering other stories of wartime childhood from people all over the country, and this enthralling, sometimes very funny and always surprising collection, Children of the Blitz, is the result.

It is easy to see where he got the idea for The Machine Gunners, because wartime children seem to have amassed impressive arsenals stripped from crashed planes and stowed away in cupboards or under the bed. Bullets were nothing - a penny each in the playground: one lot of boys set up a machine gun and cannon on the church roof to shoot at enemy planes, while another picked up an unexploded bomb and took it home on the back of a bike (it slipped down on the way . . .).

Then there were stern headmistresses and borough surveyors, all dutifully reported to the police as spies, PoW camps to be infiltrated, Americans to be imitated and an air raid shelter complete with everything except a roof.Attitudes were not all as we might expect either: an evacuee in Folkestone consoled herself not with letters home but with communist dogma,and a Tyneside schoolboy was told he ought to be thinking of going to university after he accused Harris and Churchill of war crimes in a school debate.

But there is more to be done with memories than just retelling them, and Robert Westall turned four such incidents into powerful and vivid fiction in Blitz, some of the last pieces he wrote before his death in 1993. Maggie hears strange noises from the attic which turn out to be far more devastating than her spooky imaginings, and Rosie, caught in an air raid, dives into a full shelter where something just isn’t right.

A crashed airman in a shocked state of euphoria has to be enticed out of his plane before it explodes; and there is both tension and comedy when you start driving the police around during an invasion alert - with a consignment of black market butter in the back. Robert Westall captures the real essence of wartime childhood: no heroes, no goody-goodies, but a sense of the excitement - both fearful and fun - of ordinary life lived at the edge of danger.

There is danger too in Jayne Pettit’s treatment of childhood resistance A Time to Fight Back, what with underground newspapers in occupied Belgium and round-ups of Jews in Romania. These are tales of real courage which deserve to be recorded. There is drama too, as one French schoolboy denounces another boy in his class to the Germans, but the writing lacks the sort of grittiness that makes Westall’s characters so believable. Even the villains turn out to be victims of extenuating circumstances.

On the other hand, of course, Anne Frank believed that people are essentially good, and she had more reason than most of us to doubt it. Dear Anne Frank stems from a project set up by the Anne Frank Educational Trust and Puffin Books, inviting modern children to write to Anne. Some of the letters take the sort of line one might expect, marvelling at how she survived so long in the attic, and some worry about the propriety of reading her private diary.

On the other hand, one wrote to Anne in the character of the imaginary “Kitty” to whom she addressed her diary, and one boy, hauntingly, imagined himself the person who betrayed them to the Gestapo. It is very clear how directly the diary speaks to children - many letters are particularly shocked that the Germans impounded Anne’s bike and many writers reflect sombrely on how little the world has changed since Anne’s time. “World Peace. World eternal peace”, writes one 12-year-old girl from Sussex; “Chances of that happening by itself - zero to infinitive. Chances of it happening with us all trying - infinitive to zero. I guess it’s time to go make sure I’m nicer to my sister”.