Northern Ireland Secretary Peter Hain has accused Conservatives of abandoning the cross-party approach to the Northern Ireland peace process, and has called on the party's new leader, David Cameron, to restore co-operation.
Mr Hain said it was "a great shame" that Tories had put up opposition to "essential building blocks" of the process, such as the amnesty for IRA prisoners on the run from justice.
The government was "entitled" to the same level of support from the opposition as Labour gave John Major when he was negotiating the first ceasefires in the 1990s, he said.
The issue of so-called "on-the-runs" is one of the largest remaining stumbling blocks in the way of the restoration of devolved institutions in Northern Ireland, which have been suspended since the Stormontgate spying scandal of 2002.
Mr Hain is particularly angry that the Tories have been trying to block the Northern Ireland Offences Bill which would allow terror suspects - who have never faced court for alleged outrages committed before the Good Friday agreement - to escape jail.
In an interview published yesterday on website www.ePolitix.com, he said: "I think there is a need for more inclusivity on the floor of the House of Commons. It's not to say you can't have an argument over a detail in a bill, but when it is an essential building block to getting peace then we are entitled to their support, having backed them on similar, if not even more controversial, moves.
The Conservatives' attitude is in stark contrast to Labour's approach when John Major's government was negotiating with the IRA, said Mr Hain. "The opposition parties used to support the government, as we did when we were in opposition and John Major started talking to the IRA.
"We supported him and it was a tough thing to do; people didn't like the fact that we supported the government when the IRA had only recently being setting off bombs. They set off the bomb in Canary Wharf after his government started negotiating with the IRA, and we still backed the Tories' dialogue with them." He called on Conservative leader David Cameron to change his party's approach.
"I think we are entitled to expect more bi-partisan support from the opposition than we've got in recent times," he said. "I hope there will be a fresh approach under the new Tory leadership," Mr Hain said.
"I think it is a great shame that the bi-partisan policy which helped deliver peace and stability - unparalleled peace and stability for Northern Ireland - should have been broken by the opposition in recent years."
Shadow Northern Ireland secretary David Lidington described Mr Hain's comments as "regrettable".
"We continue to operate a bi-partisan policy on Northern Ireland wherever possible, which sometimes involves giving the government the benefit of the doubt," he told the BBC Radio 4 Today programme.
"But on this bill we are looking at something that would allow people who have committed barbaric murders, things like the Enniskillen Poppy Day massacre, to go free without serving one day in prison or even appearing themselves in court." (PA)