ITV presenter Phillip Schofield came under fire after he handed Prime Minister David Cameron a list of alleged paedophiles during a live TV interview.
The list of Conservative Party figures, drawn from gossip circulating on the internet, was accidentally exposed to the cameras in a way which meant the names were visible to millions of TV viewers.
A Downing Street source described the ambush on ITV1's This Morning as a "silly stunt", while Mr Cameron himself warned against a witch hunt against people who are gay.
The Prime Minister appealed to anybody with information to contact the police, but raised concern about the internet speculation about who might be embroiled in the scandal relating to abuse at children's homes in north Wales dating back to the 1970s and 1980s.
Mr Schofield later apologised if the names had been visible as a result of a "misjudged camera angle", and stressed that he was not intending to launch a witch hunt. During the interview the presenter - apparently without warning - handed the PM a card carrying the list of names, which he said he had found in a cursory trawl of the internet.
He asked Mr Cameron: "You know the names on that piece of paper. Will you be speaking to those people?" Although Schofield was clearly attempting to keep the card turned away from the cameras and the names were only visible for a fraction of a second, it is possible that the identities of individuals may have been disclosed, potentially leaving ITV exposed to legal action.
A Downing Street source described the broadcaster's actions as "irresponsible", adding: "This silly stunt has resulted in people's names being put out there. They will want to vigorously defend themselves.
"The Prime Minister has taken necessary serious action on child abuse allegations. He is also concerned about a separate issue where people are facing an internet witch hunt. It's important allegations are handled properly - and people's reputations are not unnecessarily smeared."
Taking the card, Mr Cameron warned: "There is a danger if we are not careful that this can turn into a sort of witch hunt, particularly about people who are gay, and I'm worried about the sort of thing you are doing right now, taking a list of names off the internet. If anyone has any information about anyone who's a paedophile, no matter how high up in society they are, that is what the police are for."
He added: "I've heard all sorts of names bandied around and what then tends to happen is everyone sits around and speculates about people, some of whom are alive, some of whom are dead. I do think it's very important that anyone who's got any information about any paedophile, no matter how high up in the country or whether they are alive or dead, go to the police."
