He pounced. She pounced. Gasp

Hugo Barnacle is absorbed by a vigorous family saga with a soft centre; The Facts of Life by Patrick Gale Flamingo, pounds 15.99

There was a vogue in the Seventies for turning TV sitcoms into feature films. From the dire George and Mildred to the decent Likely Lads the films had one common flaw: the script, by sheer force of writer's habit, always came out like two TV episodes stuck together.

Patrick Gale, who established himself with a swift succession of short novels a while back, has now tried something longer, but the resulting 500-page family saga is really two books in one cover. Part I, set just after the war, has the young composer Edward, a convalescent TB case, romancing and marrying his doctor, Sally. Part II, set nowadays, has the couple's gay grandson, Jamie, contracting Aids, losing his smart job at Lloyd's and dying bravely, while his sister, Alison, abandons her career to set up an Aids "respite centre".

Part I is the more satisfactory. It offers the best writing, both in hand-picked phrases, like the description of the Norfolk garden stream - "Beneath the surface, wigs of emerald weed shook in the current" - and in sustained passages like the great climactic flood.

Oddly, given the period setting, this first half also offers the more convincing atmosphere, post-war shabbiness evoked with unstudied ease, though the chronology may be wobbly - if Edward was only 14 when his German- Jewish parents sent him to school over here in 1936, he can't have done two years at Cambridge before war broke out.

All the same, the storytelling is vigorous. Gale is good at piling on the emotion, switching between idyll and upheaval in the manner that has brought bestselling fame to Gabriel Garcia Marquez and Catherine Cookson alike.

In Part II, we hit some major problems, particularly with Jamie's great love, Sam the hunky builder. "Huge," it says here, blond, laconic, mysterious, he embodies far too many cliches of homosexual fantasy, including the worst of all: he isn't gay. No, sir. Not one bit. He simply happens to fall hopelessly in love with Jamie at first sight, that's all.

"I'm just a bloke, not some fantasy of yours," he says; the effect is not convincing. Gale adds, "Sam looked up with searing directness," which makes it even flakier. Now and then Sam is given to sudden explosive rage. This is meant to be dead macho, elemental, the Lawrentian life-force or something - Jamie and Alison certainly think so - but it just comes across as deeply queeny.

Jamie explains the attraction of a bit of rough by suggesting that "social differences provide an equivalent of gender difference". The equivalent of children, meanwhile, is usually small dogs, but Sam can do better than that. On a wild impulse he takes Alison and recklessly impregnates her. This means the dying Jamie sees her swell up and senses the joy of vicarious parenthood before he goes.

When panting Sam pounces, Alison remembers Jamie's words, "He just took over. I didn't have any will any more." She thinks it's all wrong. "But," says Gale, "she could not pretend... that a part of her was not eager for what was happening." There's a bit of Victorian porn in The Faber Book of Seductions that goes just like that.

Not merely by excluding all conscious humour, but by narrating with conviction and eliciting genuine sympathy for the characters (well, some of them), Gale manages to stall the full realisation of the book's absurdity, allowing the reader a good old wallow. Heartwarming sad-happy tosh like this does take some skill: remember they gave Marquez the Nobel for it.

Jamie's attitude to Aids is quite educational. Before Sam, he was on three pick-ups a week and he tells his counsellor he would do it all again. When he finds he probably got the bug from a blood transfusion after a skiing accident, he is mortified.

This is because sexually-acquired Aids is an "honourable" death, met while asserting one's identity. Purely accidental Aids is for "women and children". Which is not an original novelistic insight, just a basic tenet of gay orthodoxy, but Gale does illuminate its perverse logic for those who may not be familiar with it.

Of his laboured attempts to draw a parallel between Aids and the Holocaust, however, the less said the better.