The 17-year-old Soho hostess, the PR guru and a classic sting: it's enough to make an MP sick

Those who inhabit the strange world of sex scandals knew about it weeks ago. The 17-year-old girl - "I'm not old enough to vote but I'm old enough to know when I've been used" - was certainly in on the act last week, if not from the start.

In fact, the only person who knew nothing about the hackneyed plot unfolding around him was the patsy: Tory MP Piers Merchant, exposed in the Sun yesterday as the girl's lover.

As Fleet Street farces go, this was anything but original. It had all the classic elements of the cliche-ridden tabloid sting to a degree that was almost surreal. There was the blonde "Soho hostess" Anna Cox, who claimed she felt "used" after having sex with the glamorous MP. They met, she said, in suspiciously stylised Sunspeak, last month at a Young Conservatives function and an affair began.

On Tuesday, when he should have been canvassing support in defence of his 15,285 majority in Beckenham, Kent, Mr Merchant was frolicking in a nearby park with Miss Cox. A Sun photographer was there. Later, Miss Cox was pictured entering the MP's flat in Pimlico, and pictured again leaving it on Wednesday morning. Again, the Sun was there.

Miss Cox, who works in a bar where sex is performed for clients who pay pounds 250 for her company - "I don't sleep with them. I just sit there" - was presented as a victim. But it is understood she was paid in the region of pounds 25,000 for her services, which included being photographed performing a sex act with the MP.

"When he first seduced me, he surrounded the mattress with scented candles," she said. "But last night [Tuesday] it was straight down to business. The sex did nothing for me and I've realised too late what an awful mistake I've made."

Yet there can be little sympathy for the "victim" - himself something of a Tory cliche: a 46-year-old right-winger, purveyor of family values and Europhobe. A man who, when confronted with pictures of his infidelity, said: "You must have a very weird sense of values if you see anything wrong with me kissing a girl in the park."

Yesterday, as support for Mr Merchant dwindled, there were more cliches. There was the supportive wife, Helen, who in the classic tradition of Tory scandals, appeared on her doorstep, standing by her man and then giving him a passionate kiss for the benefit of the cameras.

The only old chestnut that was missing was the Tory grandee voicing strident support for the miscreant before dismissing him. In his absence, it was the Deputy Prime Minister, Michael Heseltine, who said he was sure Mr Merchant would like to consider his position. No surprise then, that Mr Merchant's views on Europe clash spectacularly with Mr Heseltine's.

So, was it a set-up? You bet.

Max Clifford, the PR guru and avowed bete noire of the Tory party, the man who brought us the alleged young boyfriend of Jerry Hayes, said the sting was not one of his, but he was indirectly involved. Sources close to him said yesterday that he was approached by a third party several weeks ago and asked whether he would handle the story. He said he would become involved only if there was evidence and mistress was prepared to talk.

It is understood the caller approached Mr Clifford again last week to say the girl was ready to meet him. The caller then sought advice on how much the story was worth and which paper would best handle it.

Mr Clifford estimated it was worth up to pounds 50,000 and said that the Labour- supporting Sun would be the ideal platform. His involvement ended there and, according to sources, he did not take his usual 20 per cent. But the result was the same. The intermediary approached the Sun, Miss Cox was brought on board and the head of Mr Merchant was delivered on a plate.

Last night, the MP's attempts to keep a low profile were shattered when he appeared on BBC 2 in a pre-recorded programme, Politicians on Parade, in which he and other MPs were put through their paces in the military.

The programme provided a humorous end to the play that had unfolded throughout the day, with cringingly apt comments like: "It feels rather like being on the most daring fairground ride - only repeated continuously with no opportunity to get off." He was talking about a hair-raising flight in an RAF fighter jet.

But perhaps the highlight was when his fellow participant, Labour's Gerry Steinberg, let slip that Mr Merchant had been sick during the flight.

"Were you actually sick?" asked the presenter. "No," replied Mr Merchant. But, as his eyes darted in spectacularly unconvincing fashion across the screen, one thing became clear: Piers Merchant made a very bad liar.