British Prime Minister David Cameron ordered an investigation on Monday into the way claims of child abuse in Wales were examined after a victim said an unidentified Conservative Party figure had abused children in social care in the 1970s.
Speaking during a trade mission to the United Arab Emirates, Cameron said the allegations, aired by the BBC's flagship current affairs programme Newsnight, were so grave that they needed further investigation.
The unmasking of late BBC star presenter Jimmy Savile as one of Britain's most prolific sex offenders has prompted wider concern that some powerful paedophiles from the 1970s and 1980s may have used their influence to avoid punishment.
Steven Messham, one of hundreds of victims of sexual abuse at children's care homes in Wales over two decades, told the programme that he had been sexually abused by a prominent Conservative political figure and others in the late 1970s.
"Child abuse is an absolutely hateful and abhorrent crime and these allegations are truly dreadful and they mustn't be left hanging in the air, so I'm taking action today," Cameron said.
"I'm going to be asking a senior independent figure to lead an urgent investigation into whether the original inquiry was properly constituted and properly did its job, and to report urgently to the government."
Cameron said Messham, who had asked to meet him, would be granted a meeting with the minister for Wales.
It was impossible immediately to verify Messham's claims. The Newsnight reporter said he could not name the figure because there was "simply not enough evidence to name names".
The state-funded broadcaster is itself grappling with hundreds of abuse allegations against Savile, a cigar-chomping DJ turned television star who victims now say used his influence to mask a lifetime of sexual abuse of young children.
Messham, who gave evidence in 2000 at an inquiry into child abuse, told the BBC that he had been abused "more than a dozen times" by the Conservative figure.
"You were just sexually abused, various things would happen, drink would be involved. It was basically rape, but there wouldn't be just him, there would be other people involved as well," Messham said.
The Telegraph news website said it had spoken to the politician at the centre of the accusations and he had denied the claims. He said if the BBC named him, he would sue for libel.
"I've never been to this children's home. The fact is that if they publish anything about me they will get a writ in the morning, I wouldn't wait two minutes," the Telegraph quoted the politician as saying.
Lawyers for some of Savile's victims say their clients have indicated there was an organised paedophile ring at the BBC at the height of Savile's fame in the 1970s and 1980s.
Police have so far arrested glam rock singer Gary Glitter and comedian Freddie Starr as part of their investigations. Both men have been released on bail.
The abuse claims against Savile have also sullied the reputation of the BBC. Newsnight itself pulled out of airing a planned report on the abuse claims against Savile last year.
Cameron has said the sex abuse allegations leave the BBC and other institutions with serious questions to answer.