Owen Paterson is to announce early next year whether a public inquiry will be held into the shooting of Pat Finucane

The security services offered to hand over secret files on the murder of a Catholic lawyer shot dead by loyalist gunmen who were allegedly colluding with the state, according to WikiLeaks.

The claim about the Pat Finucane case is contained in the latest round of US diplomatic cables published by the controversial whistleblowing website.

The solicitor was gunned down at his home in Belfast in 1989 in front of his wife and three young children. The killing was one of the most notorious of the Troubles with persistent claims that the security forces facilitated the loyalists who carried it out.

According to the documents, published by the Guardian newspaper, former Irish prime minister Bertie Ahern told US diplomats that "everyone knows the UK was involved" in the murder.

Northern Ireland Secretary of State Owen Paterson is to announce early next year whether a public inquiry will be held into the shooting of the high-profile lawyer, who counted alleged IRA members among his clients.

The apparent offer by M15 is revealed in a cable written by US ambassador to Dublin James Kenny in June 2005 after a meeting with US envoy to Ireland Mitchell Reiss.

Mr Reiss had himself just held talks with then head of the organisation Eliza Manningham Buller.

She reportedly told Mr Reiss she would be willing to hand over MI5's case files to any public inquiry, but she wanted the inquiry to proceed under the terms of new legislation introduced in 2005.

The cable read: "Reiss briefed him on his talks in London, including with the head of MI5, who committed to turning over all evidence her agency has to the inquiry, but she was adamant that the inquiry will proceed using the new legislation."

Part of that legislation allows for sensitive materials to be withheld from any final report published by the inquiry.

PA