Running time: 113 mins CLINT EASTWOOD and Jack Nicholson think nothing of acting their age. Harrison Ford, too. Now it's Bruce Willis's turn. Except that he acts older than he is. Ageing is actually the best prop an actor can draw on, at least if they're male. In Richard Donner's terrific action thriller 16 Blocks, Willis . . . looking 10 years older than the 51 he is . . . is Jack Mosley, a balding, broken down NYPD detective with a limp who needs a bottle of Jack Daniels to struggle through his daily shift. His eyes are bloodshot and watery, his blood vessels bloated. Even talking is an effort.

At the end of a shift one morning Mosley's dumped with the seemingly routine task of driving petty criminal Eddie Bunker from the lock-up to the courthouse 16 blocks away to testify before a grand jury. It doesn't help that Bunker . . . played by the rapper Mos Def . . . is a motor-mouth who just won't shut up and keeps going on about how he's going straight and going to start a bakery in Portland, Oregon. "People can change, " he insists. Mosley, breaking his morose silence, growls, "They can't."

What Mosley and Def don't know . . .

but the audience does . . . is that a van with two rogue cops is stalking them, determined to prevent Def reaching the courthouse alive. The grand jury is investigating police corruption and Def has testimony that could prove crucial . . . but it must be given before the jury is released in just 60 minutes' time.

Mosley got the job of escorting Bunker precisely because he's a deadbeat and can be relied on not to act the hero and get in the way. Realising he's been taken for a patsy he cussedly tries to act again as the cop he once was, even if he barely has the strength to draw a gun. 16 Blocks explodes into a cat-andmouse ticking-clock chase pitching Mosley and a hand-cuffed Def against virtually the entire New York City Police Department, which has been misled into thinking Mosley and Def rather than their pursuers . . . led by David Morse . . . are on a shooting spree, killing cops and putting civilians in peril.

Veteran director Richard Donner, the creative force behind The Omen, Superman and Lethal Weapon, shows his mastery of genre entertainment by seamlessly combining three familiar scenarios into a compelling characterdriven drama shot.

It's shot mostly with hand-held cameras, more or less in real time, within the framework of a flashback that turns into present tense in a spectacular bus-hijacking denouement. "I was trying to do the right thing, " Mosley dictates into a tape recorder in the opening scene as a SWAT squad closes in on him. The suspense is in waiting to see what happened next as the action unravels.

16 Blocks is part Midnight Run (the odd-couple buddy theme), part Dog Day Afternoon (offbeat hostage showdown) and part Prince of the City (police corruption), but 100% Willis at his best.

Willis is a strangely underrated actor, perhaps due to the flip wise-cracking persona he acquired in his breakthrough TV series Moonlighting and his subsequent celebrity status as the former Mr Demi Moore . . . not to mention the Die Hard movies that put him in the $20m a movie bracket. Yet getting his first break from Sidney Lumet in The Verdict in 1982, he has gone on to give pivotal performances in such challenging movies as Pulp Fiction, Twelve Monkeys, The Sixth Sense and, last year, Sin City. If 16 Blocks had been released later this year, it might have made him a serious contender for an Oscar nomination. Perhaps it still will.