Clive Lewis said he was keeping his promise to his constituents as he resigned from the shadow cabinet after failing to obey his leader's three-line whip to back the Brexit bill.

The Norwich South MP was one of 122 MPs who refused to give Theresa May their authority to formally begin Brexit in an overwhelming House of Commons vote after 40 hours of debate.

But the European Union (Notification of Withdrawal Bill) was still approved at third reading with a majority of 372. All the other Norfolk, Suffolk and Fenland MPs voted for the bill, apart from Liberal Democrat Norman Lamb, who abstained.

Norwich voters supported Brexit by a margin of 56pc to 44pc - the only constituency in the three counties to have a remain majority.

After a raft of amendments, including to guarantee the rights of EU citizens already living in the UK, were rejected, Mr Lewis announced that he was standing down from his shadow business secretary post to vote against triggering Article 50.

He said: '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 Corbyn, who ordered his MPs to back the bill, praised Mr Lewis who was an early backer of his leadership bid, saying he was an asset to the Labour Party and their movement.

He said he understood the difficulties of MPs in remain voting constituencies, but added: 'MPs have a duty to represent their constituents as well as their party. However, the Labour Party respects the outcome of the EU referendum, so we have asked all Labour MPs to vote for the Bill at its third reading tonight. We have been clear from the start that Labour will not frustrate the triggering of Article 50, which represents the start of the process for leaving the EU.'

The legislation will now have to pass through the House of Lords before Mrs May can invoke Article 50. A total of 52 Labour MPs rebelled and former Conservative chancellor Ken Clarke also voted against the Bill.