Retired Canadian judge Peter Cory has strongly criticised British government proposals which would limit the scope of any new public inquiries into cases such as the killing of Belfast solicitor Pat Finucane.
Judge Cory has investigated a number of controversial killings in Northern Ireland.
In a letter to the head of a US Congressional Committee sub-committee on Human Rights in Northern Ireland, Judge Cory said he could not contemplate any self-respecting Canadian judge accepting an appointment to an inquiry constituted under the proposed act.
He described the current proposals as creating an ‘intolerable Alice in Wonderland situation’.
In a letter to Congressman Chris Smith, which was read out at a hearing in Washington, Judge Cory said it seemed to him that the proposed new act would make a meaningful inquiry impossible, and that any commissions would be working in an impossible situation.
The government minister, the actions of whose ministry was to be reviewed by the public inquiry, would have the authority to thwart the efforts of the inquiry at every step, Judge Cory said.
Mr Finucane's family, human rights activists, nationalists and some Labour MPs fear the proposed legislation will be used to limit information to the public in future inquiries, and not just those dealing with issues affecting Northern Ireland.
The solicitor's family, which met senior US and Irish politicians this week during St Patrick's Day events in Washington, has warned that it will not co-operate with an inquiry into his murder which is established under the new legislation.
Mr Finucane was shot dead by loyalist gunmen at his north Belfast home in 1989.