For this by-election, John Robertson was selected as the Labour candidate and was sponsored by the Scottish Miners' Federation.
This was the first instance in the 1910-18 parliament in which Liberal and Labour candidates had opposed each other.
Labour's intervention to contest this Liberal seat gave the Unionists a real hope of winning.
Following boundary changes, most of the seat made up Bothwell for the 1918 general election.
Millar moved on to contest neighbouring Motherwell where he was defeated.