Labour’s former Kensington MP has quit the party, saying it is “unrecognisable” under Sir Keir Starmer’s leadership.
Emma Dent Coad, a Kensington and Chelsea councillor who led the local Labour group, was a key ally of Jeremy Corbyn.
At the 2017 general election she won a shock victory over the Conservatives by just 20 votes, but narrowly lost the seat to the Tories at the 2019 poll.
Announcing she had resigned from the Labour party on Thursday, Ms Dent Coad said: “I’m not leaving the party, the party has left me.
“It is unrecognisable. I will continue to sit on Kensington and Chelsea Council as an independent.”
Ms Dent Coad, a prominent Grenfell campaigner, last year said she had been blocked from standing as an MP for the party at the next election.
Her exclusion was one of a number where leftwingers were removed from Labour parliamentary candidate lists.
Ms Dent Coad’s decision to leave the party comes after Diane Abbott was suspended as a Labour MP.
In a letter to the Observer newspaper, the Hackney North and Stoke Newington MP suggested Jewish, Irish and Traveller people were not subject to racism “all their lives”.
Sir Keir Starmervowed to "root out" anti-semitism within Labour after complaints Jewish people faced prejudice in the party under the leadership of Mr Corbyn.
Under Mr Corbyn's leadership, the party was investigated by the Equality and Human Rights Commission (EHRC) and found to have acted unlawfully.
Labour stripped Ms Abbott of the whip and launched an investigation following the publication of her letter.
On Thursday Sir Keir told ITV that Ms Abbott, as Britian’s first black woman MP, had been probably been subjected to “more abuse than any other person in public life”.
But he added that his “gut feeling” was that her letter was “anti-semitic”.
“I'm determined to change the Labour Party, so that the Labour Party and anti-semitism and not mentioned in the same sentence,” he said.
“We've done a huge amount of work on that and I was really pleased that many of the Jewish community feel much more confident in the Labour Party than they did but this battle against anti-semitism is is never over.”