'It was a tremendous personal performance, and a remarkable performance. The way he dealt with Paisley was impassioned, and totally effective,' one Cabinet minister on the right of the party said.
Tory MPs privately said that if the IRA resumed their terrorist campaign in the new year, it would not be Mr Major who would take the blame. 'He has taken a risk in talking to the IRA. The IRA are tired and do want to give up. It's now up to Gerry Adams to convince his army council,' said one Tory MP with a security background.
Pro-Unionist Tory MPs gave a cautious welcome to the statement. Andrew Hunter, chairman of the Tory backbench Northern Ireland committee, said it was Mr Major's most effective performance since the general election.
'There was some concern expressed immediately before the details were known at the neutral role that the Government has adopted rather than a pro-Unionist role, but I think on reflection, many Tory MPs will see the inevitability and the justice of that. You can't have the referee playing for one side,' Mr Hunter said.
The Government subdued the hostile reaction it feared from some Tory MPs by holding a private briefing minutes before the Prime Minister's statement. In a conference room below the chamber, Sir Patrick Mayhew, Secretary of State for Northern Ireland, assured 40 pro-Unionist MPs the guarantees for the Unionists were cast-iron.
The main doubters were Tory MPs who had rebelled against the Government over the Maastricht treaty. Only faint signs of their concerns surfaced in the chamber. One leading anti-Maastricht Tory said he was holding fire until later.
In the Lords, Lord Tebbit, the most outspoken Tory critic of Mr Major's peace efforts with the IRA, warned that paragraph four of the declaration contained a right of the Irish Republic to share sovereignty over services in the North, without the need for legislation.
One senior Opposition peer said the Prime Minister had invested his personal reputation in the initiative and had been forced to deliver a statement, which contained nothing new. 'He is on an escalator and could not get off it. The worst thing is the public has been made to think that peace depends on the IRA. It's about a political settlement, but Major has built up the IRA.'
However, the peer declined to be quoted by name, underlining the anxiety of the main Opposition parties to preserve the bipartisan approach to peace. John Smith, the Labour leader, said: 'I welcome this declaration with enthusiasm and I fervently hope it will be the first step in a peace process which will lead to a political settlement.'
Ian Paisley and Peter Robinson, of the Democratic Ulster Unionists, condemned the declaration. 'You have sold Ulster to buy off the fiendish Republican scum,' Mr Paisley told Mr Major in a protest letter to Downing Street.
But MPs noted the more cautious response of the Ulster Unionist Party, particularly from David Trimble, regarded by many as the heir apparent, who said Ulster people would need 'some convincing' that Sinn Fein and the IRA had renounced violence. But the UUP did not reject the declaration.
Army sources reacted cautiously to speculation about a possible IRA ceasefire and ruled out an early reduction in the 19,000 British service personnel serving in Ulster.