Four weeks today, we’ll know whether Scotland has decided to become an independent country or stay within the United Kingdom.

If the union remains intact, the loudest sigh of relief could well come from the Labour party. Scotland sent 41 Labour MPs to Westminster in 2010, and has returned a similar-sized wedge for the past 50 years. Even in Labour’s nadir of 1983, Scotland dutifully elected 41 Labour members.

This consistency has fostered a perception that without Scotland, Labour’s chances of winning any kind of majority at a general election would be severely diminished.

But this is a misconception. Of all the elections held in the past 50 years, only four would have had a different outcome had Scotland been absent from the UK: 2010, 1964, and the contests of February and October 1974.

Without Scotland, the 2010 election would have resulted in a Tory government. This graph contrasts the actual result with, on the right, the notional result based on a parliament of 591 seats instead of 650, and hence a target of 296 for a majority:
None of the triple victories of Margaret Thatcher or Tony Blair, or the victory of John Major in 1992, would result in a different outcome if Scotland is subtracted from the distribution of seats.

We have to go right back to 1974 for more examples – two, to be precise.

The overall outcome of the election of February 1974 would have still been a hung parliament, but with the Tories in front of Labour instead of vice versa.
Edward Heath might have been able to continue as prime minister of a minority government – though probably not for very long, given the ongoing miners’ strike, three-day week and energy crisis.

Take Scotland out of the October 1974 result, and Labour would not have won outright but instead have ended up the largest party in a hung parliament:
The fourth and final election of the last 50 years in which the Scottish seats were crucial took place almost precisely half a century ago.

The election of October 1964 would have ended not in a small Labour victory, but an even smaller win for the Tories:
I can’t imagine a government reliant on a majority of one would have survived for very long, but it would at least have allowed Alec Douglas-Home to escape the ignominious historical category of “prime ministers who never won a general election”.

As for 2015, Labour’s “red wedge” of Scottish seats will probably make a difference to the outcome, but I suspect only in the extent to which the party emerges the largest in a hung parliament. A look back at recent history suggests these kind of factors only become relevant when the country is on its way to or from extended periods of landslide governments.

That so few elections of the past 50 years fall into this category touches upon another issue: the benefits or otherwise of a first-past-the-post electoral system. But that, at least in this election, is not up for debate.