Downing Street has condemned a "silly stunt" by This Morning presenter Phillip Schofield after he handed David Cameron a list of alleged Tory paedophiles live on air.
Appearing on the ITV programme, the Prime Minister was handed a card with a list of names by Schofield, who said he found the names after he spent "about three minutes" trawling the internet.
The presenter ran the risk of dropping the TV programme into a legal quagmire, as the names on the card were visible to the viewers.
Cameron was quick to criticise Schofield's ambush after he was asked if he would be speaking to the people on the list, adding he fears allegations a senior Tory MP raped a boy at a North Wales care home could develop into a "witch-hunt against people who are gay."
Cameron had appeared on the show to discuss his recently lauchend Dementia Friends scheme.
Cameron said: "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 alive or dead, go to the police. This is very important.
"There is a danger if we are not careful that this can turn into a sort of witchhunt, 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."
A No10 source told the Daily Mail: "This silly stunt has resulted in people's names being put out there. They will want to vigorously defend themselves."
Following the incident, Schofield issued an apology and said it was not his intent for the list to be viewable.
The presenter said: "If any viewer was able to identify anyone listed, I would like to apologise and stress that was never my intention.
"I was not accusing anyone of anything and it is essential that it is understood that I would never be part of any kind of witch hunt.
"Unfortunately there may have been a misjudged camera angle for a split second as I showed the Prime Minister some information I had obtained from the internet.
"I asked for his reaction to give him the opportunity to make a point which he very clearly made about the dangers of any witch hunt."
The Prime Minister's spokesman said in a briefing: "We should not have a trial by Twitter. People should not be throwing about unsubstantiated allegations."
Cameron previously said he was taking a "close interest" in allegations that an unnamed senior Tory from the Thatcher-era was involved in a paedophile ring at the Bryn Estyn care home in Wrexham.
Speaking under parliamentary privilege at Prime Minister's Questions, Labour MP Tom Watson also said there was "clear intelligence of a widespread paedophile ring" involving a senior aide of a former prime minister.
Cameron added during This Morning: "I would say to Tom Watson and all those people who are quite rightly inquiring into all of this, if you have got information, we are a civilised democratic country under a rule of law, with a police force, with a justice system, go to the police."
The government has confirmed it is to launch an inquiry into the sexual abuse allegations.
Cameron said: "I want to find out what happened in north Wales. The fastest way of finding out is with the judge that I've appointed.
"The idea that if you had one mega inquiry that you'd speed everything up, I'm not sure this is true.
"I don't rule out taking further steps. I want the Government to be absolutely on top of this, I don't want anything to be covered up. If there are more things we have to do, we will do them."