Lord of the Nutcracker Men

This book,has one of the most interesting plots I have read in a long time. The story goes as a boy, in 1915, his father has gone to war, but has made him a set of magical soldiers toys and building, guns etc. The magical soldiers toys at first look like a normal set of toys, but it is actually real war soldiers, as in each toy soldier is a real man on battle. Anyways, the boy( John) doesn't realise this until his battles are very similar to the real battles. His dad, also sends him a model of himself, but it shows the decaying health, as the suit turns from red to moldy brown, etc. He stops playing with the nutcracker men, on the "Christmas Truce of 1914", and luckily, 4 years later, his dad returns home.