All he could have said was 'I helped develop an extremely powerful weapon, that will annihilate the World’ but that is hardly a ‘Secret’, brilliant scientists on both sides must have been aware of the devastating effects of such 'extremely powerful weapons'?

He has a doctorate in history; so, if that’s any measure, he is qualified enough to treat the subject with imaginative insight and a high degree of verisimilitude and empathy. Unfortunately, however, the main vehicle which he has chosen to set out his alternative history is a poorly written thriller with all of the typical problems of that genre - unrealistic characters, clunky dialogue, reliance on co-incidence and worst of all exposition masquerading as narration.

Then there is a ring of course of pro-resistance people scattered in the Bureaucracy who regularly spy for the Resistance.

Sansom offers us an alternative Britain in Dominion, a Britain occupied by Nazi Germany where Britain has become Hitler’s greatest ally.If he were not already Mister Shardlake I am convinced that this book would have gathered rejection slips rather than accolades from the likes of the Guardian and the Independent. Sansom also nails his colours to the mast about the sadness of the descent into Brexit ( I share his views).

Britain is now governed by a crypto-fascist regime headed by Max Aitken and Lord Beaverbrook, the press magnate.

But though I have never read a Harris book that was less than five stars, this one of Sansom's, I'm afraid, is closer to four. Subsequently Britain surrenders to the threat of Nazi invasion and becomes a puppet state of the Third Reich. Being David's best friend I assumed his point of view would be used and was surprised that it wasn't but it didn't ruin the book at all that it wasn't. The idea of a Nazi puppet state Britain following a peace settlement in 1940 is an interesting background for a book, but Sansom really didn't exploit it.

Oswald Mosley, whose fascist party made substantial gains in the rigged parliamentary election of 1950, is Home Secretary, in charge of the normal police and black-shirt recruited auxiliaries. The antagonist, Gunther Hoth, a Gestapo policeman hunting Fitzgerald and his Resistance colleagues, is neither stupid nor inexperienced and almost becomes a sympathetic character. In Dominion this same Beaverbrook is a man prepared to hand over Britain’s Jewish community to the Nazis.Part adventure, part espionage, all encompassed by terrific atmosphere and a well-argued "it might have been". If you think I'm being pedantic then yes, I am, but it's lack of accuracy such as this that leaves the reader doubting the accuracy of everything else. Seriously, does anyone in the real world say things like, for instance, "Sometimes I wonder what the world would be like if we had not fought Argentina in 1982? Neville Chamberlain, the Prime Minister, has announced his intention to resign, discredited by Britain’s disastrous campaign against the Germans in Norway.