The National Crime Agency chief will lead a new investigation into child abuse claims in north Wales linked to a senior Tory politician, says Theresa May.

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The home secretary told MPs that the inquiry would report back by April 2013.

Keith Bristow will lead investigations into new claims about sex offences against youngsters in the 1970s and 1980s, and review how previous inquiries were carried out by the police. The Serious Organised Crime Agency and Child Exploitation and Online Protection Centre experts will also take part in the review.

"The government is treating these allegations with the utmost seriousness," Ms May told MPs. "Child abuse is a hateful, abhorrent and disgusting crime, and we must not allow these allegations to go unanswered, and I therefore urge anybody who has information relating to these allegations to go to the police."

Following David Cameron's pledge yesterday, Downing Street said later on Tuesday that Mrs Justice Julia Wendy Macur will lead a separate review into the "scope and conduct" of the original Waterhouse Inquiry into allegations of child abuse at north Wales care homes.

The original inquiry investigated allegations that emerged in the 1970s and 1980s from children in care who said they were subject to sexual and physical abuse at the Bryn Estyn children's home [pictured] and others in north Wales.

Mrs May said she would also consider Labour's calls for a wider, over-arching inquiry into child abuse - including the allegations involving the late DJ and BBC presenter Jimmy Savile - if the evidence was shown to justify it.

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Previous inquiries

The inquiries follow claims made late last week that the Waterhouse inquiry failed to name suspected abusers because lawyers said it was defamatory.

Steve Messham said that the inquiry did not look at abuse outside the care homes, and he renewed allegations against the police and several individuals.

Let's see the criminal investigations pursue their route and then, if there is a case for this to go wider, then of course the government will look at that. Theresa May

Mrs May said: "The report found no evidence of a paedophile ring beyond the care system which was the basis of the rumours that followed the original police investigation, and indeed one of the allegations that has been made in the last week."

A 1991 North Wales Police probe led to seven convictions against former care workers involved in abuse. Then in 1996 Sir Ronald Waterhouse's inquiry, set-up and backed by successive former Welsh secretaries, sat for 203 days and heard evidence from 650 people, with more than 80 people named as abusers - mainly care workers and teachers.

There were 140 compensation claims settled on behalf of the victims and 72 recommendations were made.

Mr Messham met with Welsh Secretary David Jones on Tuesday and said that while he was optimistic about what would happen, he said he was not confident about how a second inquiry would be conducted.

"I haven't got confidence that it's going to be done properly yet, I've got to be convinced of that," he said speaking outside the Wales Office on Whitehall, where the meeting took place. "After all's said and done, when the inquiry was announced, that was a Tory government. We're back to a Tory government. Let's just see how it goes."

One overarching inquiry?

Shadow home secretary Yvette Cooper said that she welcomed an investigation to find out whether there was a cover up, the was concerned that there were too many separate inquiries runing parallel. Her call for a single over-arching public inquiry was echoed by a number MPs from across the House.

"Of course we need to get to the bottom of what is happening in each case, but at the moment the framework the government has set out risks being very confused. We have to have a proper way to learn the right lessons for the current framework for safeguarding children."

Mrs May did not rule out a widespread individual inquiry: "Let's see the criminal investigations pursue their route and then, if there is a case for this to go wider, then of course the government will look at that."

Labour MP Tom Watson, who has written a series of blogs on the allegations of child abuse at the time, said he was concerned that numerous narrow inquiries were not the solution, and that they could in fact lead to a cover-up.

He said all abuse "from Wales to Whitehall" needed to be investigated. "Can Theresa May live with what she's just announced - the next stage of a cover-up?" he asked.

Mrs May confirmed that the police investigation would be able to go wherever the evidence took it. "If there are any avenues to pursue in terms of criminal investigations then the police should take those wherever they go," she said.