I have not read the book but will after reading the other reviews.
This is a very heartwrenching. sensitive, touching waretime film about an boy evacuated from London to stay with a widowed man in the country and how he gradually settles in to life there. He terrified to be suddenly summoned back to his Mum in London and Mr Tom searches for him when he gets no news from him. There is a close friendship between William and another boy in the village.
The transformation of Mr Tom and William during the story is wonderful.
Do please watch out for the expression on Mr Tom's face when William learns to ride his friend's bike. Superb acting. It's a real tearjerker and I get a lump in my throat every time....wonderful