Shadow Business Secretary Clive Lewis has resigned amid the vote on Brexit
The shock resignation came as MPs voted on whether Prime Minister Theresa May should be allowed to trigger Article 50 and start the formal process for the UK to leave the EU.
Mr Lewis is the fourth shadow MP to leave as the UK negotiates its future.
He stepped down from the shadow cabinet.
He said in a statement: "When I became the MP for Norwich South, I promised my constituents I would be 'Norwich's voice in Westminster, not Westminster's voice in Norwich'.
"I therefore cannot, in all good conscience, vote for something I believe will ultimately harm the city I have the honour to represent, love and call home.
"It is therefore with a heavy heart that I have decided to resign from the shadow cabinet."
Mr Lewis added that working with the shadow cabinet and Labour Party leader My Corbyn had "been a privilege."
He added that he would "continue to support our party and our leader from the back benches to the very best of my ability."
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