The election was triggered when, on 30 June 2008, the sitting MP David Marshall stood down due to ill health.

It is one of the most deprived constituencies in the UK, with 30% of the working-age population on unemployment or incapacity benefit and nearly 40% of children growing up in homes where there is no adult in paid employment.

On 28 June 2008, Marshall informed local party leaders that he would be stepping down on medical advice, after 10 weeks of sick leave from the House of Commons.

[4] On 30 June 2008 Marshall accepted the post of Steward and Bailiff of the Manor of Northstead,[5] a device allowing him in effect to resign as an MP, triggering the by-election[6] The election gained attention throughout the UK due to worsening results for Labour during 2008.

The by-election also came within days of the controversial resignation of the Scottish Labour leader Wendy Alexander, with voting for a replacement not taking place before polling.

In a Scotland-wide opinion poll of Westminster voting intentions, released on 11 July, the SNP was on 33%, with Labour on 29%, Conservatives on 20% Lib Dem on 14%.

[10] However, in an opinion poll conducted solely within the Glasgow East constituency, released on 12 July, Labour led on 47%, SNP on 33%, Liberal Democrats on 9% and the Conservatives on 7%.

The SNP chose John Mason,[12] a longtime resident of the constituency, and leader of the opposition on Glasgow City Council.