Caught in a tabloid trap

A seemingly friendly chat with a former confidant led to Jeffery Archer's downfall. The secretly taped conversation was a classic example of a newspaper "sting", writes BBC News Online's Chris Horrie.

Subterfuge is a time-honoured and perfectly legal tradition in British journalism, as Jeffrey Archer found to his cost.

Ted Francis: Did deal with tabloid

His former friend, Ted Francis, had secretly taped their discussion about a false alibi at the behest of a newspaper.

It was a classic and highly effective example of a "sting" masterminded by the News of the World, which has turned journalistic subterfuge into an art form.

Investigative reporters routinely claim to be somebody they are not in order to get people to divulge information they would never normally reveal to a reporter.

Using false identities in internet chat rooms to draw out paedophiles, terrorists and fraudsters is also popular.

Lawrence Dallaglio: Taped talking about drug abuse

None of this is illegal, so long as nobody impersonates a police officer, medical doctor or priest.

But subterfuge can only be used as a last resort, and if publication is in the public interest.

What constitutes the public interest is defined by the Press Complaints Commission, the newspaper industry's self-regulating watchdog, as:

Exposing crime;

Protecting public health and safety;

Preventing the public from being misled.

So it's perfectly OK for a journalist to pose as somebody trying to buy drugs in order to unmask a dealer.

William Straw: His father took a hard line on drugs

That's what happened when the Mirror bought a small quantity of cannabis from the then Home Secretary Jack Straw's son, William, two years ago.

During the last Tory government, Sunday Times reporters posed as businessmen offering to bribe MPs to ask questions in the House of Commons.

The politicians involved complained of entrapment and, more generally, of dishonest and sneaky behaviour.

But the reporters were on rock solid ground and - when the MPs appeared to accept the money - had the tapes to prove their story.

Red in the face

Less clearcut is the use of subterfuge to reveal the sexual peccadilloes of the famous.

John Major: Gave tabloids a green light

If the victim is a public figure who has previously denounced sexual promiscuity, then journalists can claim they're preventing the public from being misled.

However, finding out that a local bank manager likes to watch porn videos doesn't justify publication. If it was a vicar, head teacher or an anti-pornography campaigner, that would be a different matter.

John Major's family values campaign failed in part because it provided a "public interest" excuse for the tabloids to detail the extra-marital adventures of a string of Tory backbenchers which they had previously not dared print.

Cut and dried

Using a secret tape recorder may be sneaky, but it's perfectly legal.

Donal MacIntyre wired up with hidden cameras

The tactic is routinely used by investigative reporters on newspapers such as News of the World. But unless the subject is told they're being recorded, the tapes can't normally be used in court.

The rules for television and radio journalists are even stricter, especially if the tapes are for broadcast.

In recent years, investigative programmes such as BBC One's MacIntyre Uncovered have come to rely almost entirely on secret filming to infiltrate groups such as football hooligans.

MacIntyre would've been required to show that he knew in advance of any wrong-doing, there was no other way to prove it, and the public would benefit from finding out.

Bait and see

But "fishing expeditions" - infiltrating or secretly recording in the hope that something turns up - are not allowed.

Stung: Sophie Wessex

This was one of the allegations made against News of the World journalist Mazher Mahmood when he secretly taped Sophie, Countess of Wessex, apparently suggesting that money could buy introductions to the Royal Family.

The reporter, working on a tip-off from a disaffected former employee of the Countess's PR company, posed as a Gulf businessman offering a contract to promote tourism in Dubai.

The public interest justification was that the man managing the PR firm lacked high ethical standards and, therefore, could damage the monarchy.

Having set up a meeting with the countess, Mahmood turned the conversation to the Royal family and recorded Sophie's comments about her in-laws.

Few commentators doubt that it was this "tittle tattle" that grabbed readers' attention, rather than any perceived threat to the constitution.

Gossip for gossip's sake

It's often suggested that hypocritical use of the public interest defence could lead to tighter legislation which would make legitimate subterfuge more difficult.

News of the World's Rebekah Wade with partner Ross Kemp

Some journalists already fear that the right to privacy enshrined in the Human Rights Act might one day make secret taping illegal.

But, for the time being, anyone with a secret to hide ought to be very careful about accepting invitations to expensive restaurants from long-lost friends or enthusiastic new clients.

They might turn out to be undercover journalists wedded to the idea that when it comes to investigative reporting, there's no such thing as a free lunch.