Labour frontbenchers who defied Jeremy Corbyn in the Commons Brexit vote will be sent a formal written warning over their behaviour 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.
Convention dictates that members of the leader’s shadow team should resign or be sacked if they defy such an order.
Some did resign, including shadow business secretary Clive Lewis, who was replaced by Rebecca Long-Bailey.
But, after a meeting between Mr Corbyn and his chief whip Nick Brown, the remaining rebels will receive only a letter insisting that they must “comply with the whip” in the future.
When the government brought its Brexit Bill to the Commons, Mr Corbyn said Labour would not seek to obstruct the EU referendum result.
To ensure as many of his MPs supported him as possible, he imposed a three-line whip, the strictest instruction to vote with the party.
BBC political correspondent Chris Mason says the formal warnings leave the prospect, unless they are moved, of three whips trying to persuade their colleagues to vote with a leader who himself rebelled against Labour more than 400 times in government – and when they themselves have also defied him.
There are still a “couple of vacancies” to be filled in Mr Corbyn’s shadow team but it is not expected there will be any further announcements until next week.
It has been announced that Ian Lavery and Andrew Gwynne have been appointed joint national elections and campaign coordinators for Labour.
Jon Trickett has become shadow minister for the Cabinet Office and will remain shadow Lord President of the Council.
In Wednesday’s vote, the draft legislation was approved by 494 votes to 122, 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.