By the time you read this, the word referendum will be as stale as bread on a bird table, and about as appetising.

I wouldn't wonder if it was already banned in many households, either to keep the peace or to simply give weary tongues a rest. Nevertheless, the date is fast approaching when another momentous vote will be taken, this one on membership of the European Union. It is this potentially cataclysmic occasion that hangs over the plot of Andrew Marr's debut novel like an executioner's axe.

First, a word of caution. Those entering Marr's fictional world might expect a sober work, in keeping with his public persona. As a journalist and broadcaster, Marr is one of the political corps's most articulate, searching commentators, whether on air or in print. For an all too brief time he was the face to be found in front of No 10 whenever there was a story, his pungent, informed views adding a depth of knowledge and hinterland to proceedings that many of us wished our political leaders shared.

That version of Marr, however, has been banished to the cellar. One cannot even hear his muffled cries as Marr the novelist is let loose, rampaging through the corridors of Whitehall and Westminster with the rebel yell of a schoolboy on the last day of term.

Set three years hence, when Scotland is still part of the Union, the Queen is dead and Charles on the throne, Head Of State takes place in the frantic run-up to the European vote. Opening with the discovery of two corpses, one headless and handless, the other the apparent suicide of a lovelorn journalist, it is a political thriller in the mould of Tom Sharpe, albeit less funny, but no less farcical. One can't help speculating whether, during his recuperation from ill-health, Marr saw the treachery, spin and ruthlessness that underpins political life for the almost circus act it is.

His intention to have fun is evident from the start, in his description of the editor of the National Courier, Ken Cooper, whose every thought and word begins with f. It does not need Marr to inform the reader that he modelled himself on the legendary Scottish editor, Charlie Wilson, once famed for hurling a typewriter through a (closed) window.

In his lampoon of the newspaper world, the author's love of the inky, murky, splenetic and occasionally noble profession is one step shy of nostalgic, informed no doubt from his rookie days at The Scotsman: "All newspaper offices are much the same - the filthy beige walls, the desolate expanse of cluttered desks behind which old sacks of human indolence order the young and stupid about."

The Courier's floor is, to this reader's eye at least, a great deal more appetising than Marr's depiction of the labyrinths of political power in London and the home counties, where much of the action takes place. As the Pro-Europe camp, led by the popular Prime Minister, suffers a calamity, the PM's team leaps into action with more vigour than Jason Bourne, and such cunning one assumes they have Peter Mandelson on their side. The enemy camp, meanwhile, is led by the siren-like Olivia Kite, whose young aide, Jennifer, finds herself in desperate danger, thanks to her poor choice in men.

What Marr lacks in fictional sophistication he makes up for in gleeful mischief. Dusting the pages with sly nods to friends and allies - Nick Robinson has been knighted, there's a Scot called Nelson Fraser who wears a foul-smelling sporran, and the author's own TV show gets a mention - Head Of State also reveals Marr's innate educationist.

When, for instance, a heroine is on the run, he takes a moment to observe, as she speeds away from London: "The A12 had begun life ringing to the clatter, curses and alien commands of sweating Roman legionaries as they built what was first known as the Inter V, a dead-straight spear jabbing north-east from Londinium. But it had been badly mucked about with by the locals after the Italians with their German work ethic had gone home." With his non-fiction head frequently appearing over the parapet, like the ballcock in a cistern, he also deals briskly but effectively with sex: "they bucked like deer and squirmed like eels. And after that, vice-versa."

Add an eastern European gangster, a cast of caricatured but all too recognisable media and political pawns, and a turncoat who makes Machiavelli look about as shifty as Rowan Williams, Head Of State is a rip-roaring cackle at the expense of an establishment that one hopes can take a joke.