In 1935, the Unionist Party (the precursor to the Conservative Party in Scotland) won 42% of the vote in Scotland. They took half of the Scottish seats in the House of Commons. If you add their coalition partners in the National Government, they controlled 60% of the seats. The political map of Scotland was almost as blue as the Saltire.
By 1997, the Conservatives had been completely wiped out north of the border. Tory bastions in the leafier suburbs of Edinburgh and the rural expanses of the Grampians and the Borders had been lost to Labour, the SNP and the Liberal Democrats.
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By 2005, the Conservatives had recovered a single Scottish MP by taking the new and cumbersomely named border constituency of Dumfriesshire, Clydesdale and Tweeddale.
Scotland had become a Labour stronghold, safely delivering over 40 Labour MPs each and every election since 1964. With the landslide 1997 election, Scottish Labour hit a high watermark of 56 Scottish MPs.
Even when devolution prompted a reduction of the total number of Scottish MPs from 72 to 59 in 2005, Labour still took a healthy 41 MPs to Westminster.
What a difference a decade makes. This election looks set to be as cataclysmic for Labour in Scotland as 1997 was for the Conservatives.
If 2015 does mark the start of a new political era for Scotland, it could be a long time before it changes. The Liberals were the dominant force in Scotland in the mid-19th century. This gave way to a strong Unionist Scotland in the first half of the 20th century which, in turn, gave way to Labour hegemony north of the border.
If the pattern of Scotland’s 70-year itches stays true to form, the SNP could be Westminster’s third largest party for years to come.