Sinn Féin was today accused of selling out on the families of victims of alleged state murders and collusion in Northern Ireland.
SDLP leader Mark Durkan also called on Sinn Féin party president Gerry Adams to withdraw his support for the controversial legislation involving so-called on the runs which is passing through Westminster.
Under the proposed new laws, members of the security forces allegedly involved in killings would not have to stand trial - a deal with the republican leadership agreed with the Irish and British governments, according to Mr Durkan.
If and when the legislation is passed, several republicans who fled Northern Ireland years ago after being allegedly involved in terrorism will be free to return home without running the risk of going to jail.
Tribunals of inquiry into any charges they could face will be held in their absence.
Mr Durkan said: "In return for the greater advantage of getting their on the runs back with no questions asked, Sinn Féin sold out the families that for years they claimed to fight for.
"They let state killers and loyalists totally off the hook."
Yesterday in London, Mr Adams said no members of the security forces involved in killings should be free from prosecution.
Mr Durkan added: "But if a panicked Gerry Adams is now changing position, there is a simple thing that he must do - call on Tony Blair to withdraw this legislation immediately and entirely.
"That is what Gerry Adams must now do. The British have made clear that they do not like this legislation. So Sinn Féin should release them from the side deal and call the whole thing off."