Just because you're paranoid...

Conspiracy Theory Richard Donner (15) The Full Monty Peter Cattaneo (15)

Conspiracy Theory is a decent thriller with a good performance by Mel Gibson and one sublimely preposterous moment. Gibson's character Jerry is an unstable taxi-driver obsessed with conspiracies. He publishes a newsletter of wild speculation, and when nuns get in his cab he feels called upon to lecture them about "the festering scab that is the Vatican". He also has a compulsion to seek out and buy copies of a book he doesn't even like - The Catcher in the Rye.

Jerry has theories about virtually every aspect of American life, from the space shuttle really being a weapon that causes earthquakes to Oliver Stone being a spokesman for George Bush ("The fact that he's still alive says it all"), but even he doesn't suspect what is going on. Every time he buys a copy of Salinger's novel to set next to the unread dozens on his shelves, the bookshop's computerised till communicates his whereabouts to the dark forces that monitor him. The moment the bar code is read in Barnes & Noble, helicopters begin to disgorge sinister figures on to the streets of Manhattan, and motorcycles rev up inside mysterious trucks.

Catcher in the Rye is symbolically the right choice of book by screenwriter Brian Helgeland, because of its supposed role in inspiring the assassination of John Lennon, and the sequence works well in genre terms: the film moves up a gear with the revelation that Gerry's paranoid suspicion is too mild a response to the world around him. It's only afterwards you start thinking how many copies of Salinger's book - a classic high-school English assignment - get sold every year in New York. But by then the director, Richard Donner, old hand at hokum that he is, has eased you past a whole new bunch of untenable plot points.

The film's maelstrom of McGuffins would be even harder to swallow if the plot didn't emerge, bit by bit, from the hero's monologues. Jerry sometimes forgets he has no passenger and spins theories over his shoulder to the empty back seat. By the time the credit sequence is over, Mel Gibson has spoken more words than he did in the whole of Mad Max. His character in the Lethal Weapon series was an earlier sketch of instability, but Jerry Fletcher is a much more thoroughgoing portrait. Jerry has a lock on his fridge, and on the food containers inside it. His confusions of memory, when he tries to convince the woman he loves from afar that he is on to something ("I was right - what was I right about?"), are affecting, and in one action sequence, tethered to a wheelchair and interrogated while pumped full of hallucinogenic drugs, his eyes taped open like Alex in A Clockwork Orange, he breaks one of the great unwritten rules of the movies, that heroes don't scream.

In the 1970s, looking for conspiracies was an activity that could be politically effective (All the President's Men, Three Days of the Condor) or suicidal (The Parallax View), and the heroes either way were journalists and newspapers. Now paranoia has become general in a dilute form, a pose of disillusion, with most people feeling that the world is full of secrets and the newspapers full of lies, with the novel corollary that no one anywhere can know everything. Jerry in Conspiracy Theory isn't even interested in plots for which there is any evidence, since loose threads are the sure sign of a botched job and an insignificant cover-up. The film itself is full of loose ends, and it's doubtful if even the screenwriter could explain the plot chronologically.

As Alice, the young woman in the Justice Department watched over by Jerry, Julia Roberts reins in her trademark grin until the last sequence. Till then, it's all preoccupation and angst. Alice keeps her demons at bay with punishing sessions on the jogging machine, while Jerry spies on her tenderly from his cab. In one sequence of voyeuristic love, the director rises briefly above the slickly workmanlike. Jerry sees Alice mouthing words as she jogs, and tunes his radio until the music matches. She's singing "Can't Take My Eyes Off You", and he joins ineptly in. It's their tune, though she doesn't know it yet.The scene deepens and justifies Jerry's love, but it's also a textbook illustration of an unchanged image transformed by sound, a distant figure brought suddenly close as if by love.

Mel Gibson's face is showing some human wear at last, and he must be glad to be past his Bird on a Wire days, when the camera couldn't make up its mind between his twinkly eyes and his twinkly bottom. The characters in the new British film The Full Monty get their kit off in public, but not because they're nature's Chippendales - that's the whole point. Gaz (Robert Carlyle) and the boys rise above the obstacles of being variously too thin, too fat, too old, rhythmically defective, terrified of getting aroused in public or terrified of failing to.

The film starts with footage from Sheffield - City on the Move, a 1970s promo-documentary praising the town's industrial muscle and love of fun. Then comes the title "25 Years Later"... in today's Sheffield, masculinity is in crisis, economically, in the family, emotionally and sexually. Gaz is behind on his maintenance payments, truculent at the Job Club, and about to lose his rights of access to nine-year-old Nathan (William Snape), who is in any case embarrassed by his dad's shiftlessness and inarticulate affection.

The women of South Yorkshire may be surprised to learn from The Full Monty that they have replaced men in every area of life, plunging the other sex into trauma. In one early sequence of Peter Cattaneo's film a woman attending a Chippendale show uses the gents' urinal - standing up - while Gaz watches horrified from a toilet stall. The writing is on the porcelain wall.

Simon Beaufoy's script more or less forces Gaz into forming an amateur troupe of male strippers. He needs pounds 700 to make good his arrears of maintenance, or he loses his son. Stripping is presented as an act of desperation, something a man would only do when pride became a luxury out of his range. But by the time the boys do finally appear on stage, the project has been oddly transformed. For all the emphasised Englishness of the setting and the people - the gnomes, garden sheds, canals and Mars bars - a lot of American-style growth has gone on. The men have bonded, have talked about feelings, and have reached a point where taking their clothes off, even with men in the audience, is a demonstration of self-esteem, not an act of despair.

The Full Monty is a comedy, to be sure, and often an entertaining one - waiting in the dole queue, the men start gyrating, first faintly and then more freely, to a Donna Summer record on the radio. When they are arrested for rehearsing in an abandoned factory building, they pretend to be stealing girders until the security video shows the shameful truth. Gerald (Tom Wilkinson), the closest thing they have to a choreographer, takes the opportunity to rewind the tape so as to show Gaz where he always goes wrong in the routine. A policeman offers critical comment.

The fault of the film is not that it deals in wishful thinking but that its style of wishful thinking - assertive, benignly narcissistic, dedicated to overcoming fears - is imported, a graft job. The people in the film would be much more likely to see success as a form of class betrayal and defeat than as a badge of solidarity. It's no coincidence that the film's funniest sequence is in this, the domestic grain. Dave (Mark Addy), the tubby one, has stolen a video of Flashdance, as instructed. When the lads sit down to watch it, Dave in his innocence doesn't see a fable of self-realisation, with Jennifer Beals paying dues in a factory until she can prove herself as a dancer and shake her sweat on to the world. All he sees is a second-rate welder who hasn't got the knack of acetylene - a lass whose welds won't holdn

Both films on release tomorrow