Image copyright PA Image caption Jeremy Corbyn imposed a three-line whip on his MPs in the Brexit vote

Labour frontbenchers who defied Jeremy Corbyn in this week's Commons Brexit vote will be sent a formal written warning but will not be sacked.

Mr Corbyn had imposed a three-line whip on his MPs to vote to back Brexit.

But 52 Labour MPs rebelled in Wednesday's vote, including 11 junior shadow ministers and three whips, whose job it is to impose party discipline.

Clive Lewis, who quit the shadow cabinet over the vote, said rumours of a leadership bid by him were "fantasy".

Mr Corbyn imposed the three-line whip after vowing his party would not seek to obstruct the implementation of the EU referendum result.

Convention dictates that members of the leader's shadow cabinet team should resign or be sacked if they defy such an order.

Some did resign but the remaining rebels are to receive only a letter insisting that they must comply with the whip in the future.

The decision not to sack them leaves Labour facing the prospect of three whips trying to persuade their colleagues to vote with a leader who himself rebelled against Labour more than 400 times - when they have defied him themselves, BBC political correspondent Chris Mason says.

Mr Lewis has since been replaced as shadow business secretary by Rebecca Long-Bailey.

The churn in Corbyn's shadow cabinet

Speaking to the Eastern Daily Press, Mr Lewis, who is MP for Norwich, said his resignation was not the beginning of a bid to challenge Mr Corbyn for the party leadership, adding that he was "working hard" to support him from the back benches.

A string of resignations from the Labour front bench mean there are still a "couple of vacancies" to be filled but it is not expected there will be any further announcements until next week.

New appointments announced on Friday include Ian Lavery and Andrew Gwynne, who become joint national elections and campaign coordinators.

Jon Trickett has become shadow minister for the Cabinet Office and will remain shadow Lord President of the Council.

Corbyn's Shadow Cabinet Team turnover since Sep 2015 4 Shadow Cabinet re-shuffles in 18 months 32 resignations, of whom...

4 later returned to top positions

4 of those who quit, did so to vote against the Brexit Bill PA

The draft Brexit legislation was approved by 494 votes to 122 in Wednesday's vote and now moves to the House of Lords.

Prime Minister Theresa May wants to trigger formal Brexit talks by the end of March.

She will do this by invoking Article 50 of the Lisbon Treaty but requires Parliament's permission before doing so.