Senior Tory politicians took part in drink and drug-fuelled sex parties with underage boys during seaside conferences, it was claimed today.

Former activist Anthony Gilberthorpe says he was handed cash and told to ‘fetch entertainment’ - code for young boys – by members of Margaret Thatcher’s government.

But the claims were today rejected as ‘tittle-tattle’ by former Conservative minister David Mellor, who insisted those named were dead and unable to defend themselves.

Former activist Anthony Gilberthorpe, left, claims he was asked to find underage boys for sex during Tory party conferences when Margaret Thatcher was leader in the early 1980s

Westminster has been gripped by claims of an Establishment cover-up of allegations of child sex abuse over several decades.

The government has appointed former High Court judge Baroness Butler-Sloss to lead a wide-ranging panel inquiry into abuse at every level of society.

Mr Gilberthorpe says he will give the inquiry the names of former Tory ministers, some of whom are still alive, who he claims he saw with young men at party conferences.

He claims he sent a 40-page dossier to Mrs Thatcher in 1989 detailing Cabinet ministers who took part in the sex parties, bur says he was warned off by a senior civil servant.

He told the Sunday Mirror how boys as young as 15 were plied with alcohol and cocaine at Conservative gatherings in Blackpool and Brighton in the 1980s.

He named former former-Education Secretary Keith Joseph, ex-local government minister Rhodes Boyson, and Michael Havers, the former attorney general who is the brother of Baroness Butler-Sloss. All of those Mr Gilberthorpe names are now dead.

Mr Gilberthorpe alleges that during the 1983 party conference in Blackpool he was asked by Dr Alistair Smith, the Conservative party chairman in Scotland, to find young boys for two Cabinet ministers to have sex with.

The ministers are not named, but he does claim that Mr Boyson and Mr Joseph were there.

Mr Gilberthorpe told the Sunday Mirror: 'Dr Smith, who I looked up to at the time and was the most important Tory in Scotland, told me to go and fetch some 'entertainment', which was code for young boys and handed me a handful of bank notes. There was about £120.

I was expected to find the youngest and prettiest boys. It was what those men wanted. In fact, it was all they wanted Anthony Gilberthorpe

He added: 'It was a norm and an open secret that these older members of the Tory party, like Dr Smith, paid for young men to join them at sex parties.

'I was expected to find the youngest and prettiest boys. It was what those men wanted. In fact, it was all they wanted.’

He also claimed that selected people had an Oscar award symbol on their conference pass to give them access to secret sex parties.

Mr Gilberthorpe alleges that in 1981 he went to a party in Blackpool where ‘several boys who were clearly aged between 15 and 16’ were performing sex acts on MPs.

He claims he saw Sir Michael Havers there. Baroness Butler-Sloss has faced calls to stand down from her role leading the panel inquiry because her brother was in the Cabinet at the time many of these allegations date from.

He also claims that during the 1984 party conference in Brighton there was a sex party at the Grand Hotel on the night before an IRA bomb killed five people.

Mr Gilberthorpe says he was ‘manipulated and groomed’ by the senior politicians. ‘It is time this came to light before anyone else is abused,’ he added.

But the allegations were dismissed by Mr Mellor, a former Tory Cabinet minister who served in the Thatcher and Major governments.

Former Tory minister David Mellor, pictured today, dismissed Mr Gilberthorpe's claims as a 'lot of tittle-tattle' about people who were dead and cannot defend themselves

He told BBC One’s Andrew Marr show: ‘The only people who are named are dead. There is an opportunity to name live people.

‘What we are dealing with is a lot of tittle-tattle. Here is a chap who was annoyed that he wasn’t chosen as a Tory candidate.’

He added: ‘It names a lot of dead people. Where is the bravery in that?’

Mr Mellor said Mr Gilberthorpe had made public ‘implausible names’ in connection with the sex parties.

‘This is now open season because of a pretty shoddy dossier presented to Leon Brittan by a Tory backbencher.’

Geoffrey Dickens handed the file to the then-Home Secretary in 1983, but the Home Office says it can now not be found.

Mr Mellor, a Home Office minister from 1983-87, added: ‘The interesting thing about that dossier is nobody who has commented on it has ever seen it.’