The tactics used by News of the World reporters which led to rugby star Lawrence Dallaglio saying he took drugs sparked another row over where the boundaries of press behaviour should lie.

After years of apparent excesses in an era of bitter fighting for readers, the death of Diana, Princess of Wales ushered in a period of press self-restraint.

Encouraged by Buckingham Palace, editors respected the privacy of bereaved Princes William and Harry and their right to grieve away from the public eye.

Newspaper chiefs even promised not to overstep the limits of intruding into other people's lives.

They were praised by the Press Complaints Commission for their stance.

Dallaglio says he lied to the undercover reporters to impress them

But slowly, since the Diana tragedy, more stories revealing details of the private lives of the rich and famous have been creeping back - reflecting readers' undying taste for this kind of news.

Indeed, in the past year, the tabloids have kept the exposes coming thick and fast.

Last year The News of the World, in classic fashion, revealed that Agriculture Secretary Nick Brown was homosexual. The newspaper defended its action by arguing the information was in the public interest, but in the wake of a furore, the Sun pledged to stop "outing" gay ministers.

The death of Diana looked like it would herald a new era

The Sunday newspaper also uncovered the drug-taking of Camilla Parker-Bowles's son Tom, while the Sunday Mirror caused shockwaves by telling how Jack Straw's son had also taken drugs.

Hardly a day goes by, it seems, without the love lives of celebrities such as Anthea Turner, Paul Gascoigne, Will or Julia Carling and Paula Yates being examined in the papers.

In the same week as the Dallaglio allegations hit the front pages, the Sun turned its attention to comedian Lenny Henry and cricketer Ian Botham.

Broadsheets v tabloids

Broadsheet journalists and columnists have lined up to condemn any tactics involving set-ups by tabloid newspapers.

Nick Brown's "outing" sparked the Sun to make a pledge

David Aaranovitch wrote in the Independent: "I can live with the idea of a snorting Dallaglio (while thinking that he may have been a fool), whereas I can hardly bear to inhabit the same planet as the tabloid journalists who outed him. Dallaglio has, after all, done no one any harm. He does not seek to destroy other people's lives for the entertainment of others or for his own personal gain."

And the News of the World was criticised by the Daily Telegraph for its methods: "No conceivable public interest has been served by his entrapment... How long would a Nelson have been allowed to serve his country if Phil Hall, the editor of the News of the World, had been around at the time, exposing secrets and demanding exemplary virtue of the great?"

But News of the World managing editor Stuart Kuttner denied that Dallaglio was the victim of a classic honeytrap operation and that he had been entrapped by a "beautiful young blonde".

He told BBC Radio 4's Today programme: "The beautiful young blonde was accompanied throughout by, if I may say so without being too sexist, a less than beautiful male reporter, somewhat older. This was not, if you like, a classic honeytrap."

Ironically, the set-up had been praised by the Daily Mail as exactly that, a "classic tabloid honeytrap".

Secrets and envy

One reason the tabloids sell so well - particularly when they splash stories about celebrities' private lives - is that we envy them, according to psychologist Dr Sheila Rossan.

Lenny Henry the subject of unwelcome attention

"We know about the public lives of the stars but if we find out what their private lives are, they become more human - it makes them more like us," she says.

"There's also a lot of envy there - it shows they have clay feet, and are fallible just like us. We prefer people who are fallible as we can identify with them.

"So you can see it in a positive way or a negative way - enjoying seeing them brought down a level. It's a mixture of both.

"It's also very much finding out things we didn't know. Secrets seem to give us a thrill, like gossip."

Lying on a date

And if, as he insists, Dallaglio lied to the undercover reporter about taking drugs in order to impress her, he was doing no more than most men who fancy a woman.

"It's a very common tactic," says Dr Rossan.

"Talk to anyone who's dating. Men try to make out they're macho. A substantial proportion at one point or another say things that aren't true, while women who are dating tend to play down their academic knowledge in case they frighten men. They are living gender stereotypes.

"What's interesting is what he [Dallaglio] thought would impress this woman - not his rugby skills, but something else he thought would be macho."