Speaking under parliamentary privilege at Prime Minister's Questions, Labour MP Tom Watson asked David Cameron to urge the Metropolitan Police to re-examine "intelligence suggesting a powerful paedophile network linked to Number 10."
"The evidence file used to convict paedophile Peter Righton [in 1992], if it still exists, contains clear intelligence of a widespread paedophile ring," Watson began.
"One of its members boasts of his links to a senior aide of a former Prime Minister, who says he could smuggle indecent images of children from abroad.
"The leads were not followed up, but if the file still exists, I want to ensure that the Metropolitan Police secure the evidence, re-examine it, and investigate clear intelligence suggesting a powerful paedophile network linked to Number 10."
The Prime Minister said he would "look very carefully and see what the Government can do to help give him [Tom Watson] the assurances he seeks."
Lord McAlpine will receive a payment of £185,000 after a settlement was reached with the BBC over false claims made in a Newsnight report.
George Entwistle will receive a 12-month salary after stepping down from the BBC, he is also reported to be entitled to his full pension.
BBC director general George Entwistle has fallen on his sword following the Newsnight child abuse scandal.