SCOTTISH Nationalists have predicted that Mr John Major's government "will be hanging entirely on an Ulster rope" by this summer.
Confirming that his party would take "great delight" in helping force Mr Major from power, the SNP leader, Mr Alex Salmond, forecast the survival of Mr Major's government would Depend entirely on the votes of the Ulster unionists.
"That's going to be where the swing votes are," he said. "It will be up to the Ulster unionists whether the Major government survives a vote of confidence."
The UUP leader, Mr David Trimble, rejected suggestions that the government's fate lay in his hands, and dismissed speculation about the erosion of Mr Major's Commons majority in the course of the year as "hypothetical".
Meanwhile, the woman who revived that speculation with her shock defection to the Liberal Democrats yesterday raised the spectre of forcing a government defeat in her Devon constituency.
Ms Emma Nicholson MP rounded angrily on her Tory critics, and declared she would be "perfectly comfortable" to take on and defeat her former allies in her Devon West and Torridge seat. Ms Nicholson had a major-city of 3,614 over the Liberal Democrats in the 1992 general-election.
Although a by-election would make no difference to Mr Major's majority - Ms Nicholson slashed that when she crossed the Commons floor - a contest would provide a powerful focus for Conservative divisions already unleashed by Ms Nicholson's defection and her stated reasons for it.
Ms Nicholson sought to exploit those divisions yesterday in an angry response to Mr Michael Portillo, the Defence Secretary who effectively welcomed her resignation, saying she was "right to leave the Conservatives" given her support for "a united states of Europe".
Mr Portillo's intervention enraged the Tory left and blew apart Mr Major's attempts to restore order and cohesion to his parliamentary ranks.
Ms Nicholson branded Mr Portillo an "utter disgrace" who should be sacked from the cabinet. "People like Michael Portillo and that clique he heads would have been on the outskirts of the old Conservative Party, and yet Michael Portillo has one of the most important cabinet posts of all,"she declared: "He should not have it. It is an utter disgrace that somebody so nationalistic, so lacking in historic understanding...holds that job."
But Tory critics maintained their fire yesterday. Mr Harry Greenway MPG said Ms Nicholson was under a moral obligation to resign from the Commons There is no doubt that the party label gets many people elected, notwithstanding the personal vote which some MPs achieve," he said.
"But given that the whole thrust of Emma Nicholson's defection was that she was taking a moral stand, she should now go all the way and quit. She now has a moral obligation more than most to resign her seat," he said.
Labour Chief Whip, Mr Donald Dewar, yesterday promised the government "a very lively time in the Commons", while cautioning against any expectations of a succession of early government defeats.