An attempt by Britain to limit the scope of an inquiry into the killing of Belfast solicitor Pat Finucane would make an independent investigation "impossible", Canadian judge Peter Cory has said.
Judge Cory investigated some of the North's most controversial killings, including Mr Finucane's, Robert Hamill in Portadown in 1997, LVF leader Billy Wright in the Maze Prison in 1997 and Rosemary Nelson in Lurgan in 1999.
The proposed Inquiries Bill would give British ministers the power to order an inquiry to hear evidence in private, and to bar the production of some evidence to protect national security.
The legislation, which would supersede the 1921 Tribunals of Inquiry Act, has already been passed by the House of Lords without any significant change and it will begin its passage in House of Commons tomorrow.
Judge Cory said yesterday: "I don't know how any self-respecting Canadian judge would be part of it in light of the restrictions on independence it would impose."
The 1921 legislation had been the only tribunal law in place when the Irish and British governments agreed in Weston Park in 2001 that the Finucane killing would be investigated. "There was only one standard for a public inquiry at the time of the Weston Park accord," said the judge.
"If this Act had been in place at the time to set up an inquiry I don't think that there is a judge who would take it on. Its provisions are too restrictive. Independence would be impossible," he said.
The judge may attend a Congressional hearing organised by Republican congressman Chris Smith in Washington on Wednesday into the 1989 killing of Mr Finucane by the UDA.
The 1921 legislation, said Judge Cory, offered "sufficient protection" to the British government "for all the things that might deal with the security of the realm".
"My view of the proposed legislation is that it would be extremely difficult to have a public inquiry that would be in any way significant," he told The Irish Times.
Serious divisions emerged on Friday in London between officials from the Northern Ireland Office, the Department of Foreign Affairs and the Department of the Taoiseach.
The Government has pushed for the Finucane inquiry to be held under the 1921 Act, or, at least, the dropping of Clause 20 of the Inquiries Bill so that British ministers would not be able to force hearings to be held in private.
Taoiseach Bertie Ahern has already warned British prime minister Tony Blair that he will raise the matter with President Bush and other senior US figures on Thursday.
The British government is also facing opposition from leading members of the British judiciary, including the head of the Bloody Sunday inquiry, Lord Saville.
The judge, whose concerns are shared by the British lord chief justice, Lord Woolf, and other legal figures, said: "I take the view that this provision makes a serious inroad into the independence of any inquiry."
