Nick Clegg yesterday led his Liberal Democrat MPs through the No lobby to vote down a Government Bill.
In the deepest split yet between the coalition parties, Liberal Democrats combined with Labour and smaller parties to delay the implementation of the boundary review – thought to be worth about 20 extra seats in the Commons to the Tories – until 2018.
For the first time since the coalition's formation in 2010, Prime Minister David Cameron agreed to set aside collective responsibility and allow Liberal Democrat ministers to vote against the Electoral Registration and Administration Bill.
Under the proposals the Glasgow North constituency would have disappeared. Most of the constituency would have moved into an enlarged Glasgow Central and also into Glasgow North West and North East.
The Conservatives were defeated by a margin of 292 to 334.
The legislation would have equalised the size of Westminster constituencies and cut the number of MPs from 650 to 600.