SET REPORT / A hard day's night: In a sleazy Hamburg bar somewhere off Ladbroke Grove, Monique Roffey watches the Beatles in action

PROP men hand out Lucky Strikes, fizz up pints of flat ginger ale, and waft great plumes of smoke everywhere. The lights dim, the cameras roll and a hot studio tucked away behind Ladbroke Grove is transformed into the infamous Kaiser Keller pub, Hamburg, 1962. And the Beatles are on stage. The early Beatles, that is. When they were a band of five, not four. When Pete Best, not Ringo, was on drums and when John Lennon's best friend Stuart Sutcliffe was on bass guitar.

Backbeat is currently being shot in North Kensington and Kentish Town. Ian Softly, who co-wrote the script, is the film's director; Stephen Woolley, just back from Los Angeles and Crying Game success, is the film's executive producer; and Sheena Napier, an Oscar nominee for Enchanted April, is responsible for ensuring that actors and extras have an authentic early Sixties look. The boys playing the Beatles are all dead ringers for the young McCartney, Harrison and Lennon; one is a musician, the others have undergone a five-month crash course in guitar. Flown in from Hollywood to play the romantic leads - Sutcliffe and the Hamburg beauty and socialite Astrid Kircherr - are Stephen Dorf and Sherilyn Fenn. And, as an extra playing a prostitute, I have spent five long and dreary days hobbling around in ridiculously pointy shoes and a Marge Simpson beehive being snogged and groped. Sutcliffe takes the starring role in the film that was denied to him in life. The guitarist, so the story goes, couldn't play a note, and often Lennon would cover for him when he made mistakes on stage. But when the others had to as well, there came the inevitable friction and pleas for him to be dumped. His most significant contribution to the band would seem to be his involvement with Astrid Kircherr, who was credited with creating their trademark mop-tops. Before push came to shove, Sutcliffe was beaten up in a bar brawl and died of a brain haemorrhage a week later.

Dorf, as Sutcliffe, skulks around the set in character with his wrap-around shades permanently wrapped around his head. Sutcliffe was an aloof and stone-like performer; while McCartney and Harrison pogoed around and played guitar cockroach-style, on their backs, Sutcliffe just stood there silently, fag clamped in pout, and plucked away at a few well-rehearsed chords. Dorf seems to have thrown himself into the part. While the other boys are friendly, unpretentious jokers given to spontaneously bursting into song and jollying along a tired and jaded crew, Dorf comes across as a self-conscious and showy Method man, given to a lot of hoo-ing and ha-ing every time a take is about to be shot. Fenn, on the other hand, is composed, attentive and polite. Some of her lines are in German and she is patient when repeating them time after time until the director is happy with both tone and inflection.

Ian Softly keeps a low profile. If he needs to speak to someone, he approaches them personally and privately - nothing is shouted from behind the camera. Almost all of the directions given to sound, lighting and extras are handled by the first assistant director, Mary Soan. Every now and then Stephen Woolley puts in an appearance and hovers like an expectant father behind the camera, arms crossed while he quietly chews his thumb off.

The Kaiser Keller, where all the scenes being shot at the moment are supposed to be taking place, was a dingy Hamburg bar where the Beatles first shot to fame. On a relatively low budget, the art director, Joseph Bennet, has transformed a bleak and airless studio into a cosy but sleazy fishing-port tavern. A massive bar adorned with stuffed seals and glazed puffer fish runs along one wall, dinky rowing boats make love seats, the ceiling is a mass of nets and anchors, and the stage, where most of the action takes place, is an exact replica of the Kaiser Keller stage, complete with bronze baby-clam floorlights.

The film production process for any non-industry person seems strange. Some shots are recorded with sound, some aren't. Sometimes we are told to clap loudly, sometimes we have to mime it. The very first time I was on set we were all supposed to mime frantic clapping and jeering while a stripper mimed her act to music fed to her via a receiver in her ear. The first take was a disaster. Everybody froze when the last of her clothes came off.

When the team aren't filming or rehearsing a take, those with no technical expertise have nothing to do. The frequent complaint about the tedium of film-making sounds like a thin and apologetic excuse for having a glamorous job. But those who complain are right. My five days on set have completely erased any further ambition to act. The hours are horrendously long, sitting in a bus for hours on end is a bore and wearing heavy make-up and a silly costume all day is a drag.

Filming is to continue until the end of the month, and then the crew fly on to Hamburg. 'Backbeat' is scheduled for release in 1994