The family of solicitor Pat Finucane have criticised NI Secretary Peter Hain after a meeting to discuss a proposed inquiry into his murder.
Mr Finucane, 39, was shot dead in front of his family
Mr Finucane, 39, was shot dead by the UDA in 1989. His family say they do not think an inquiry held under the Inquiries Act would reveal the truth.
Mr Finucane's son Michael said: "The secretary of state had every chance in the world to play a useful role.
"The indications are he's not willing to do that, neither is the government."
Mr Finucane was killed in front of his family in their north Belfast home.
It was one of the most controversial murders in 30 years of the Troubles due to allegations of security force collusion.
Retired Canadian judge Peter Cory recommended separate inquiries into Mr Finucane's murder, and three other controversial killings.
The Finucane family, human rights campaigners and nationalist politicians, as well as Judge Cory, have expressed alarm at moves by the government to ensure the tribunal into Mr Finucane's murder is held under the Inquiries Act, which was passed earlier this year.
They have claimed the act will suppress the truth about what happened, with Amnesty International saying crucial evidence could be omitted from any final report at the government's discretion.
On Tuesday, Michael Finucane said: "He (Mr Hain) consistently underlined the government's intention to hold the inquiry under the Inquiries Act.
"It renders the panel devoid of independence and retains control with the government minister through use of restriction notices.
"Therefore we doubt its capacity to get at the truth."
He said the family are now considering taking their case to the Irish government and Taoiseach Bertie Ahern.
"The only option we have is going to the other government who's a partner in this process and getting Bertie Ahern to change Tony Blair's mind."