Vaughan's chat show has a US influence

The Irish comedian found a role in Channel 4's hit comedy Father Ted and then started hosting a number of chat and comedy shows on the station, settling into his own show - So Graham Norton - in 1998.

Openly gay, he combines an arch campness with quick-witted repartee - a combination which means his sharpness rarely descends into outright rudeness.

His show is driven by stunts and spoofs and the presenter has made a speciality of embarrassing celebrities in inventive ways.

Hazards

He encourages his guests to make phone calls to unsuspecting people - such as the owners of weird websites - and encourages audience participation.

But he seems to have no problem finding celebrities prepared to face the hazards of a guest appearance.

Cabinet Office Minister Mo Mowlam took part in the first dog "wedding" on the show, while in a Comic Relief edition of the show, the Duchess of York presented Norton with a lock of Dolly Parton's hair on a velvet cushion.

Norton's guests included the Duchess of York

Other guests have included Grace Jones, Joan Rivers, Catherine Deneuve, Leslie Nielsen and Joan Collins.

A raucous ringmaster of risqu� comedy, Norton has made himself a niche in TV comedy and become one of Channel 4's chief ratings winners.

Johnny Vaughan - who also rose to stardom on Channel 4 - is trying to create rather a different niche in his new chat show on BBC One.

Major deal

Blokey rather than camp, Vaughan uses a format borrowed from US chat show host David Letterman, sitting behind a desk and using a live band for walk-on music.

Vaughan won his spurs on Channel 4's Big Breakfast show, which he started presenting in 1997 after the departure of Chris Evans.

Vaughan's 'Orrible was not a critical success

The presenter signed a major deal with the BBC after leaving the Big Breakfast and produced a comedy drama for BBC Two - 'Orrible - to mixed reviews.

His BBC One chat show - broadcast Monday to Wednesday - kicks off with the presenter's comic review of the day's news and relies on actors and comedians such as Richard E Grant, Ray Winstone and Vic Reeves for anecdotal humour.

Irreverent in content but conventional in style, Vaughan's show will need big name guests and good scripts to shine.

Ratings

But unflappable Vaughan can be an engaging host and is rarely better than when he is thinking on his feet.

Graham Norton's new show will be broadcast "post-watershed" and is set to start in May, raising the possibility of head-to-head scheduling and a ratings war.

The outcome of such a war between the old channel-mates will be finely balanced.

Norton may be more experienced at late night TV - but Vaughan will have the advantage of having been on-air for four months already.

Johnny Vaughan Tonight is broadcast at 2305 GMT on Mondays, Tuesdays and Wednesdays on BBC One and at 2100 GMT on BBC Choice.