Forget Ibiza. If it's sun, sand, sea and sex you're after then head for the Victorian waterways linking Edinburgh and Glasgow.

Well, admittedly there's not much sun. Or sand, for that matter. And the sea's in pretty short supply (though there's miles of canals).

There is, however, plenty of sex. On the towpath, in the barge hold, under a lorry and even up against a pub wall.

The, er, barge-hand indulging in all this grubby canal-side coupling is frustrated writer Joe (McGregor), a feckless young drifter working his passage.

He's launched into an affair with Ella (Swinton), the emotionally and sexually starved wife of down-to-earth barge-man Les (Mullan).

He plies the Scottish waterways carrying coal, scrap and oil in the hold of his rusting tub, happy with a pint, a game of darts and the company of his wife and son.

However, everything changes when he and Joe pull the half-naked body of a young girl out the Clyde. Does Joe know more about her than he's letting on?

Mackenzie's gripping film noir is based on the book by beat writer Alexander Trocchi - a novelist described by Irvine Welsh as the "George Best of Scottish literature".

McGregor - now something of a Hollywood fixture - returns to the Scottish roots of Trainspotting to portray a libidinous character of bleak, uncharted moral and emotional depth.

The sex here is never joyous - it's furtive and grimy and often feral in its intensity (check out the custard scene with Emily Mortimer).

The action takes place in the grim 1950s against a backdrop of Victorian industrial decay and post-war austerity.

However, it's not unrelentingly bleak - Joe's fling with Ella's blowzy sister sees her retrieving a smouldering tab from the road after an al fresco knee-trembler. That's class.

Nevertheless, the unfolding of the plot sees the carnal gourmet of the canals slipping under a tide of moral cowardice, desperation and guilt.

It's adult fare, bolstered by believable dialogue and a denouement that determinedly refuses to cop out.

Rewarding in a way a week on the Norfolk Broads could never be. See it.

Tim Evans