Anyone who tries to adapt any novel for film or television is going to have to make some sacrifices and changes in order to make their version worth watching. In this sense William Boyd does an excellent job cutting down peripheral characters and storylines. What we are left with is a story about heroism, very different heroes, against a backdrop of the imcompetence on a grand scale of the British army of 1939-1945. Perhaps most vividly some excellent dramatisations of the evacuation of Crete, an often forgotten episode of the war.
Crouchback, the main character, begins the story idealistic at the prospect of conflict, though not in a jingoistic sense, rather Crouchback hopes the war will provide a chance to prove himself on a personal level. He is inspired by Ivor Clare, a dashing guardsman who is awarded the Military Cross at Dunkirk, although he is not all he seems. Trimmer, an oppourtunistic idler, is certainly not a hero, though is seized upon by the propaganda machine as an honest British peoples hero, and his image is cultivated in the press. Finally Ricthie Hook, is certainly brave enough to be a hero but comes accross as ultimately a tragic figure, only good for the business of soldiering.
The character of Apthorpe is very different to the Apthorpe in the book, yet is exceptionally played and provides much of the stories black humour. Naval experts may notice the Royal Navy type 22 frigate, probably launched late 1970's early 1980's used in one scene, but this is only minor - one for the ship spotters! I disagree with the other reviewer, i feel the atmosphere of wartime London was evoked quite well, and anyway only a few scenes are set in England, so I don't consider this especially important.
All in all worth a look