SO what are you going to watch? Big Brother III or a shamed TV star choke on an inescapable diet of sackcloth and ashes?The BBC and Channel 4 are gearing up for one of the most exciting TV ratings battles ever joined as the third series of the reality TV phenomenon goes head-to-head with tonight's episode of Have I got News For You? on BBC 1.

SO what are you going to watch? Big Brother III or a shamed TV star choke on an inescapable diet of sackcloth and ashes?

The BBC and Channel 4 are gearing up for one of the most exciting TV ratings battles ever joined as the third series of the reality TV phenomenon goes head-to-head with tonight's episode of Have I got News For You? on BBC 1.

Beeb bosses were secretly popping the champagne corks this week when a Sunday tabloid exposed the cocaine-fuelled vice girl sex romps of its star presenter Angus Deayton, the smug, Oxford-educated host of the BBC hit irreverent news quiz show.

The seedy disclosures were a gift as rival station Channel 4 hoped to hog the limelight as Big Brother burst back on to Britain's television screens tonight.

Up to 8 million people watched the final episodes of last year's run, with some 16 million votes cast during the series, making it the channel's most successful show of 2001.

Yet even with changes to spice up this year's series - 12 contestants, a new house, tougher rules and new challenges - will the temptation to see Angus Deayton - who usually delights in ripping other celebrities to shreds - squirm on the other side prove just too irresistable?

The Star can offer a sneak preview of the relentless mickey-taking from regulars Paul Merton and Ian Hislop after HIGNFU? was filmed last night – and 45-year-old Deayton looked distinctly uncomfortable.

Both whipped out copies of the News of the World, which reported that Deayton had sex with a prostitute and on one occasion took cocaine in a hotel.

At one stage, Merton also unveiled a T-shirt featuring the front page of the newspaper, to the presenter's evident embarrassment.

Deayton, who lives with long-term partner Lise Meyer and their baby, did not realise the woman, Caroline Martin, was a prostitute and had simply "chatted her up', the News of the World said.

Deayton mentioned the incident in his opening comments, saying: "Welcome to the show. This week's loser is ... presenting it.'

Continuing the opening of the show, Deayton said: "The words pot, kettle, smug, git, good and kicking all come to mind.'

The teams, featuring guests London Mayor Ken Livingstone and comedian Dave Gorman, were then asked to look at pictures of the recent meeting between Tony Blair and Russian leader Vladimir Putin.

Merton interrupted, saying: "The story I'm interested in Angus, you and this prostitute, how did you get away without paying her?'

Hislop then pulled out a copy of the News of the World and started reading it out.

"'He made me groan all night.' What were you doing, reading the autocue?' he asked Deayton.

Both programmes go out at 9pm tonight.