The impossible title of this extraordinary book took me back to a moment nearly 20 years ago. I had walked for three days down Wadi Surdud, one of the great seasonal watercourses that cut their way towards the Red Sea through the western highlands of Yemen. The scenery was extravagant - deep chasms sculpted by floodwater, pinnacles where lightning licked at high-perched castles, the seats of South Arabian lairds. At last, the gradient decreased, and as I rounded a bend I saw in one of the occasional pools that lay in the wadi bed something I have never seen in Yemen before or since: a man fishing with rod and line. Not, of course, for salmon: this was the coarsest of coarse fishing, for minnow-sized awshaj - I think a type of barbel - with a stick for a rod and a grain of maize for bait. The incongruous scene remains in my memory, and always will. Yemen is a memorable country: "Not a day will pass in your life," wrote the Master of Belhaven, a laird from the distant north, "but you will remember some facet of that opal-land."

Here, as well as lairds and castles, we have mists and glens, kilts, dirks and the odd feud or two. But unlike in Scotland the rain is considerate, coming at known seasons and times of day. It is also somewhat sparing, and there are no natural lochs or permanent rivers, and certainly no salmon (except smoked, on HBM ambassador's canapés). So Paul Torday's debut novel is about an impossibility. It is also about belief in the impossible, and belief itself. And the remarkable thing is that a book about so deeply serious a matter can make you laugh, all the way to a last twist that's as sudden and shocking as a barbed hook.

As with all good comedy, there's a tragic underside, a story of love and loss and another of love that never was. And there is satire. Torday's aim is deadly; but then, his targets are big. Jay Vent, the British prime minister, has taken his country into wars in Iraq and Afghanistan (and elsewhere in the region: the story is set in the nearish future . . .) and has dug himself into the deepest of holes. So what does he do? Of course: he goes on digging. "We're pretty much committed to going down a particular road in the Middle East," says Vent, a graduate, like his real-life counterpart, of the White Queen's school of logic, "and it would be difficult to change that very much without people beginning to ask why we'd started down it in the first place." . . .

This is an odd artefact. It depicts an attempt to introduce salmon to rivers in the Yemeni Highlands via the largesse of a local sheikh and the expertise of a UK government agency.

The book - it can scarcely be described as a novel - is constructed from supposed diary entries, letters, emails, extracts from Hansard, fragments of autobiography, a TV game show script, transcripts of television and press interviews, Select Committee Report conclusions and interrogations of the various participants in this madcap scheme. All have differing viewpoints and narrators. As such the whole becomes diffuse and bitty.

While there is an overall narrative thread the disparate voices too often fail to suspend disbelief. Instead of being presented with a convincing rendering of a diary extract or interview transcript we are given novelistic embellishments. The diary extracts contain information that we as readers ought to have but a diarist would not find it necessary to include. In one of the interviews a respondent states a person spoke mildly when surely they would report only the relevant conversation’s content, in another there is an (uncredited) interruption which reads, “The witness became emotional after the consumption of custard creams and was incoherent. The interview was resumed after a break of four hours.” This authorial interpolation is, I suppose, intended humorously but is, instead, bathetic, if not pathetic. The Hansard extracts do not quite reflect accurately the format of Prime Minister’s Questions. While it might be said that this is a comic novel and some licence is allowable, to get details such as this last example wrong detracts from the intended effect. Infelicities such as those above totally fail to create the necessary degree of verisimilitude. The name dropping of real people as interviewers - Andrew Marr, Boris Johnson - while the politicians and aides are fictional (yet recognisable) is also a mistake.

The book is obviously meant to be a satire but its approach is so scattershot that it is difficult to tell exactly what or whom is the intended target. Is it the workings of bureaucracies, office politics, communications directors/spin doctors, career women, politicians, even Islamic terrorists? All are featured, but the focus never stays in one place for long. The only character who has any semblance of solidity is the supposedly mad sheikh; and he has no viewpoint narrative.

After the novel’s end we also have “Reading Group Notes” containing items “for discussion.” Some may find this condescending.

Salmon Fishing In The Yemen has its moments; but they are few.