There is a moment in Kazuo Ishiguro's The Remains of the Day (1988) when the narrator and protagonist, Stevens, is humiliated by guests of his Nazi sympathising employer, Lord Darlington. Asked about complex matters of economic and foreign affairs—US debt and its effects on international trade, the motivations behind Pierre Laval's declarations on North Africa—the butler finds himself unable to answer, much to the amusement and satisfaction of his tormentors. Darlington apologises in private the next day, pointing out sanguinely that the despicable little show was simply a way to prove a now self-evident truth: "We're really so slow in this country to recognize when a thing's outmoded. Other great nations know full well that to meet the challenges of each new age means discarding old, sometimes well-loved methods. Not so here in Britain." The old, well-loved "method" with which Darlington has become so disillusioned is, of course, liberal democracy.

Stevens's loyalty to his master prevents him from condemning Lord Darlington as an anti-Semitic fascist, but the reader is left thanking historical accident that the pro-fascist feeling that infected significant sections of the British establishment in the 1930s did not ever spread into the halls of real power. In Farthing, Jo Walton's latest literary hybrid, this is exactly what has happened: the Second World War ended in 1941 with the success of Rudolph Hess's peace mission, Britain and Germany negotiated what the chief British negotiator, Sir James Thirkie, dubbed "peace with Honour," and Hitler turned full attention to subduing the rest of Europe, and the USSR in particular. America, meanwhile, sunk further into isolationism and elected Charles Lindbergh as President. In short, the world has thrown up its hands and given up the fight.

Alternate histories related to Nazi Germany are of course by now a venerable institution—from Robert Harris's mainstream smash Fatherland (1993) to the stranger works of alt.history scion Harry Turtledove, the post-1945 survival of Nazi Germany is the great "what if" of the twentieth century, and fertile ground for novelists. Harris too, though setting his book in Berlin, chose to create a world in which Britain preferred to reach accommodation with Hitler rather than fight him until whatever end. In Farthing, however, this choice and its consequences is brought front and centre—the men and women who made it and live with it are the novel's protagonists, and the action takes place in the Britain which the capitulation has created.

When Sir James Thirkie is found murdered during a party at Farthing Hall, the stately home which has lent its name to the crypto-fascist set which orchestrated peace and continues to promote reactionary policies, Scotland Yard dispatch the thoughtful, Northern and secretly homosexual Inspector Carmichael to investigate. Everyone's suspicion but the detective's falls immediately on the resented Jewish husband of Lucy, the partially disowned eldest child of Lord Eversley, the master of Farthing: Thirkie's body is found mutilated and decorated with a scrap of material emblazoned with a yellow star, the compulsory Continental uniform of the Jews.

Thus the scene is set for what is in many ways a likeably traditional country house murder mystery. Farthing features a broad cast of interesting characters, a central mystery which yields its secrets only reluctantly, and a talented outsider of a policeman. In addition, however, Farthing makes more of itself than that via its dual voice structure: odd numbered chapters are in fact narrated by Lucy in a tone which is for the most part simpering without being frustrating, and privileged without being sympathetic. Though Lucy's segments sometimes become over-precious—early on in the book, she apologises for being "scatty" when in fact the writing of her segments has so far been a rather sophisticated stream of consciousness—her perspective gives us something more than Carmichael's rather straight-ahead story of a detective investigating a difficult, politically-driven crime. Lucy is in truth the book's main character, and it is she who allows us to understand the novel's premise, characters and implications.

It is Lucy, partially aware of its wrongs but also entirely inured to the entrenched privilege of her country, who enables us to perceive the retrograde nature of this version of 1949 Britain. Because she is both a product of it and a narrator liable to lengthy digression, we get a great deal of detail from her, and in the first half of the book we are nicely introduced to a very English sort of dystopia. Farthing ultimately subordinates its mystery to its history, and Lucy is the way Walton teaches us about it. The Second World War and its aftermath saw some deconstruction of Britain's stultified class system, but here there is little of the guilt which led to the welfare state, none of the comradely feeling which opened up cracks in a society which Victorians would still have recognised. Farthing Set members have passed laws which ban anyone not educated at a public school from attending University; the NHS does not exist, and the working class remains neglected and uncared for in their usual northern mining towns and southern slums; the 1911 Parliament Act is being eroded, and the Chancellor of the Exchequer is a peer. Even Carmichael is looked down on simply for the sin of hailing from Lancashire.

In his own 1940s alternate history, The Summer Isles (novel 2005), Ian R. MacLeod posited a Britain which had lost World War I to Germany and thus trod the precise path of the Weimar Republic, ending similarly in fascism. The book's principle achievement was to create a very native form of national socialism. This is crucial for any alternate history: the genre is not really one of allegory, any more than any other type of science fiction or fantasy, but rather one which must make complete internal sense and also build on what we already know about the contexts it is perverting. Therefore, if fascism in Britain is part of the alternative history, that fascism needs to be identifiably British in nature—to lazily transpose Nazi Germany to these shores would be to hand one's world to the beast of broad point-making caricature. Walton makes an excellent start, then, in suggesting a country formed by its own forces, and not the author's.

As the mystery unfolds, Carmichael becomes more and more convinced that David, Lucy's Jewish husband, is being framed. He is being made into a scapegoat. It is possible that the reader begins at this point to become concerned that allegory is rearing its head. David is perhaps the least convincing character in the novel, precisely because he is written as not merely exactingly innocent but actively saintly. He is a money-lender, but one who only lends money to poor people looking to improve their lot with a new homely small business; he feels little lasting bitterness towards any of his persecutors; he's great with children (and probably puppies and other varieties of small animal). He is, in short, less a character and more a plot point. A Jewish servant at Farthing, Mrs Smollett (an Anglicization of her Polish name of Mrs. Szmolokiewitsz, of course), is used purely to make a point, telling a story of a murdered family and a Warsaw riot which is wholly horrific but somehow also cloying and unsubtle.

Perhaps this is because the politics of Walton's Britain takes a sharp left-turn in the novel's final third, from English dystopia to Weimar Germany in 1933. Or at least such is the allegory, because Walton is clearly also aiming at present-day targets, and it thus suits her to write polemic rather than poetry. To give away some of the plot (look away now spoilerphobes), the Farthing Set's Mark Normanby is elected by the Conservative party as its new leader, displacing Anthony Eden and by the rules of Parliamentary democracy also becoming Prime Minister. His first speech promises identity cards, restrictions on religious freedom, and the investigation of any and all fringe groups for "subversives." The innocent, predictably, have nothing to fear. Get it?

Needless to say, the murder of Thirkie has been a help to Normanby's career—he wins on the sympathy vote. Two characters call Thirkie's murder Britain's own Reichstag fire—an orchestrated event which is used by the apparent victims to promote support for their otherwise radical cause. But the Reichstag was a symbol of the German nation; Sir James Thirkie is merely a politician, however successful. There is a sense that Farthing isn't really about 1940s Britain at all, but just a way to get at today's civil liberties debate. For example, homosexuality in Lucy's Britain is apparently subject to strong repression likely to get stronger, but almost no one in the novel is without their homosexual relationship or preference. This is not per se a problem—one character's suggestion that most people are Macedonian (like Alexander the Great) pretending to be Roman (or the Victorians of the ancient world) is very deliberately inserted into the text in way of explanation—but without some self-denial, self-delusion or furtiveness, the 1940s character of this world—and the power of its prejudice—is lost, and the "persecution is hypocrisy" message decidedly blunted by a mixture of simplicity and anachronism.

Slips like this are disappointing, because in other ways Farthing is a fine book—for instance, Lord Eversley, not a fascist but not brave enough to stand up against fascists, is a subtle study in the evils of inaction. Carmichael and Lucy are both engaging narrators, and the fraternal and sexual politics of the Farthing set are satisfyingly Byzantine. If Walton sometimes falls back on over-used techniques—Carmichael and his assistant asking each other questions so as to keep the reader in touch with the status of the investigation and all its possible avenues, or Lucy digressing to tell us what is in fact an important nugget of information—it is perhaps only because they are effective. It is true that Walton too many times has a character reveal something fundamental to themselves—they know about a given homosexual affair, or are members of an underground railroad for European refugees—without having signposted it once, and that this becomes frustrating and a little comical. And yet she retains our good faith by writing for the most part well-drawn characters in smooth, lightly allusive prose

So Farthing is a clever murder mystery but a rather simplistic political statement. "This is exactly how Nazi Germany started!" is not precisely a nuanced contribution to the current debate (and, in case you were wondering, yes, Carmichael has a four-line conversation with another policeman concerning the effectiveness of identity cards as a detection tool). It's a shame that Walton couldn't resist the pull of the direct parallel, since the mystery itself is enjoyable enough and the subtle first half of her novel asks far more interesting questions and offers more food for thought than the broad satire of its second. Stevens and Lord Darlington would perhaps not recognise the political crisis Walton contrives, but the reader nevertheless remains more in fear of Darlington's kind than Normanby's. Walton can write, and write well, but in seeking to teach us a rather blunt lesson, she comes close to breaking her novel's promise.

Dan Hartland is a freelance creative thinker figuring out what to think. A writer and musician of the inverted commas variety, he splits his time equally between these two things and procrastination. He comes to science fiction from outside the genre, and is a little too happy to remain a gadfly.