What swung Thatcher’s vote of no confidence was the fact that the SDLP’s Gerry Fitt (who for some reason hated Labour’s then NI secretary Roy Mason), persuaded Independent Nationalist MP Frank Maguire to vote against Callaghan - this despite the best efforts of two leftish Unionist MPs to persuade Maguire to vote for the government. Apparently Maguire’s wife Philomena ordered him to do the opposite so in the end - faced by threats from Gerry Fitt on one side and Mrs Maguire on the other, the poor man abstained and the rest is history. A year later Thatcher was Prime Minister and Maguire was to die in office, his seat to be taken by Bobby Sands.