Brexit news - live: Labour 'moving closer to new EU referendum' amid fresh party splits as ninth MP this week quits

Indy columnist John Rentoul believes that we are "on the brink of something momentous" after a week of defections. He takes a look at quitters over the last few decades and what the decisions have come to mean.

Read his column here:

Jeremy Corbyn has said he "regrets" the resignation of Dudley North MP Ian Austin. He urged him to submit himself to a by-election as he stood on a Labour manifesto.

Tory rebel Dominic Grieve is among the Conservatives threatening to quit if the prime minister pursues a no-deal Brexit.

He told the BBC: "I can't predict where I might be if the party goes completely off the rails - that's another matter.

"The government which I am supporting implementing a no-deal Brexit - what would I do? I would not be able to maintain my support of the government. I would have to leave the party."

Shadow justice secretary Richard Burgon - a close ally of Jeremy Corbyn - has accused Ian Austin of trying to undermine Labour's chances. He said the Dudley North MP should fight a by-election in his seat.

The news has been dominated today by Ian Austin's decision to quit the Labour Party over antisemitism. Here's a helpful profile of the Dudley North MP by PA.

Ian Austin's long-running battle with Jeremy Corbyn over antisemitism in the Labour Party has been shaped by his background as the adopted son of a Jewish father forced to flee the Nazis.

Before being elected as MP for Dudley North in 2005, he was an adviser to then-chancellor Gordon Brown.

His alliance with Mr Brown continued when he entered parliament, becoming his ministerial aide and then a minister for West Midlands regional affairs.

The close political relationship led Tory leader David Cameron to brand him one of Mr Brown's "boot boys".

Mr Austin, 53, also served on the opposition front benches under Ed Miliband.

He was never likely to see eye-to-eye with Mr Corbyn, a leader from the left of the party who made no secret of his discontent with the Blair-Brown New Labour era.

The issue of antisemitism, which has dogged Mr Corbyn's leadership, was the main focus of tensions between the pair.

Mr Austin's Jewish father Fred was 10 when the Nazis marched into Ostrava in what was then Czechoslovakia.

Four days later he was put on a train to England - the only member of his family able to leave - and he never saw them again.

He grew up to become a headmaster and adopted four children - including Mr Austin.

This background had a profound influence on Mr Austin and was cited as his main reason for quitting Labour

"I grew up listening to my dad - a refugee from the Holocaust - teaching me about the evils of hatred and prejudice," he said.

"One of the main reasons I joined the Labour Party as a teenager here in Dudley more than 35 years ago was to fight racism, and I could never have believed that I'd be leaving because of racism, too."

His relationship with the Labour leadership was strained for months before he took the decision to quit.

In 2018, Mr Austin found himself facing an internal investigation over alleged abusive behaviour during the party's anti-Semitism crisis.

The probe into the "heated discussion" he had with party chairman Ian Lavery was eventually dropped.

Another Labour MP on defection watch expresses her sadness at Ian Austin's resignation.