Labour MP Ian Gibson: "My position between now and the next election is untenable"
Labour MP Ian Gibson is resigning with immediate effect, triggering a by-election in his Norwich constituency.
Labour's National Executive Committee (NEC) barred Mr Gibson from standing at the next election earlier this week after criticism of his expenses claims.
Mr Gibson was censured for selling his taxpayer-funded second home to his daughter for below market rates but his local party say he was badly treated.
The Conservatives would need a 6% swing to win Norwich North from Labour.
Mr Gibson said he had been proud to serve as an MP since 1997 but following the NEC's decision, he believed his position had become "untenable".
After talking to colleagues, friends and family, he said he was doing the "honourable thing" for his constituents.
It is not clear when a by-election will be held but the prospect will be an unwelcome one for Gordon Brown, left reeling by the expenses scandal and the spate of cabinet resignations in the past few days.
With a majority of 5,459 at the last election, the seat will be a realistic target for the Conservatives.
The MP said he had been "bowed but not broken" by the NEC's move to end his career as a member of Parliament.
Mr Gibson's local constituency party has defended him, saying he was the victim of a "kangaroo court".
He had defended his expenses conduct but said he would stand down if his local party wanted him to.
Mr Gibson said he was not party to a rumoured plot to oust the prime minister but said it was clear Labour was lagging far behind in the polls and needed "radical new thinking".
Mr Gibson is one of four Labour MPs to have been told they cannot stand at the next election over their expenses.
The other three - Margaret Moran, David Chaytor and Elliot Morley - have said they will stand down at the next election.
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