It was caused by the death of the incumbent Labour Party Member of Parliament Alex Wilson on 23 March of that year.

Within days of Wilson's death, The Glasgow Herald described the by-election as 'the biggest battle the Government has faced in Scotland since the last General Election'.

[1] The SNP, which had previously won the seat in a by-election in 1967, were reported to see the contest as an important test of where political opinion in Scotland stood.

The SNP's prospective candidate, Margo MacDonald, had a high profile as a former MP and had been working in the constituency for three years.

[1] As the opening game of the 1978 FIFA World Cup was on Thursday 1 June, the by-election was held one day earlier, on the Wednesday.