There are few moments in history where you can pinpoint a single decision that brought about momentous changes as a direct result. Even when they are pinpointed, more often than not you find it is not so simple to change it. If a war or an election had gone the other way, it may seem like a single change, but it is so broad as to essential warrant hundreds if not thousands of little changes to actually happen.

Stanislav Petrov deciding not to report a nuclear alarm to his superiors that turned out to be a false alarm is one of these pinpoint moments. A few thousand voters in some marginal constituencies changing their mind thus altering the results of an election is less of a pinpoint and more of a pincushion.

Sometimes, though, an election result can depend on the decision of one person. In 1979, a motion of no-confidence in the Labour Party government led by James Callaghan was passed by a single vote, the resulting general election would be won by the opposition Conservative Party led by Margaret Thatcher. She would lead the United Kingdom as prime minister for eleven years and her party form the government for seven further years.

A single changed vote and the government would have survived the no-confidence vote… but would it have made a difference in the long term? There are numerous possibilities for the vote to be tied. What changes would they have wrought to the history of the United Kingdom if any of them had voted differently on the evening of March 28, 1979?

In a lot of examinations of alternate history, there is a temptation to try and just avoid the event altogether, but in the instance of a no-confidence vote in the Callaghan government it was perhaps inevitable without enough changes in the events of 1978-79 to stop the opposition from calling it.