It was called after the former Labour MP, Tom Fraser, resigned in order to take up the position as head of the North of Scotland Hydro-Electric Board.

The SNP took 46% of the vote in a constituency which they had not even contested at the 1966 general election held the previous year, and gained the seat from the Labour Party with a swing of nearly 38%.

Ewing did not retain the seat at the following general election, but the SNP have been continuously represented in the House of Commons ever since.

In the years before Ewing's victory, there had been other breakthroughs by nationalist parties in Britain – including Gwynfor Evans' similarly groundbreaking victory for Plaid Cymru at the 1966 Carmarthen by-election, a big advance for the SNP at the 1967 Glasgow Pollok by-election, and SNP gains in local elections, including becoming the largest party in local government in Stirling.

[10] In 2007, on the 40th anniversary of Ewing's victory, the then SNP leader Alex Salmond said: "That by-election was undoubtedly a catalyst for reform, without which the movement for a Scottish Parliament would have been delayed still further.