MPs who defect to another party should be compelled to fight a by-election within three months of crossing the floor, according to a motion tabled in the House of Commons yesterday.
Its backers say it is "morally unacceptable" and "a betrayal of their constituents" for a Member to sit in Parliament for a party other than the one he or she was elected to represent.
Now the Government is being asked to approve this course of action.
Daniel Kawczynski (C Shrewsbury and Atcham) is the sponsor of the motion. His predecessor Paul Marsden was elected as a Labour MP for the seat in 2001 and then defected to the Liberal Democrats.
Although he did not fight the last election, shortly before polling day he unsuccessfully tried to rejoin Labour. Mr Kawczynski said: "Shrewsbury voted for a Labour MP in 2001 and found themselves with a Liberal Democrat, a party which secured only 15 per cent of the vote at that election. We called on him to fight a by-election but he refused.
"I reckon that 95 per cent of the electorate vote for the party of their choice, so to change parties like this is a complete betrayal of your constituents."