UK Parliamentary by-elections, 2015 onwards (also devolved legislatures)

[Lumine]

Same thing almost happened to Major, he won a large victory against John Redwood in 1995 but had  four votes or so changes sides he would have hit a self-imposed target and resigned.

I don't think it would have been impossible for Thatcher to win in a second round as she only needed a simple majority, but what would have been the point for her? At that point and after all that had happened she would have been left heavily wounded and with little authority.

[Lumine]

Britain does recalls now? With only 10% of the vote necessary to recall an MP?

The next time a government is unpopular without an election looming the country is going to be plunged into permanent general election mode. Really doesn't seem congruent with the British election system.

Only when specific criteria is met, essentially when an MP is convicted (but the sentence isn't enough for him to automatically be thrown out) or suspended from the House (for serious stuff), and only then can a recall petition start.