Sadiq Khan is engulfed in a new race storm after it emerged he branded moderate Muslims “Uncle Toms”.
Labour’s candidate for London Mayor used the highly derogatory term during an interview with an Iranian-funded TV station.
The frowned-on phrase from the slavery era refers to a black man considered to be excessively obedient to whites.
Mr Khan used it when he was Communities Minister in the last Labour government, while talking about the need to reach out to all Muslims in the fight against extremism.
In the little-seen interview to Press TV in 2009, he said: “I wish we only spoke to people who agree with us.
“You can’t just pick and choose who you speak to, you can’t just speak to Uncle Toms.”
The video’s emergence is a big embarrassment for Mr Khan, coming just two days before polling stations open on Thursday in the contest to run the capital.
A spokesman for Sadiq said he “regrets” using the phrase.
During a radio interview last Saturday, Mr Khan himself attacked people who say ‘Uncle Tom’, saying: “It’s racist, it shouldn’t be used”.
In the interview with Press TV, Mr Khan also dubbed Britain’s foreign policy a “recruiting tool” for extremists at times.
And he encouraged campaigners to boycott goods from countries like Israel as a means of protest.
The MP for Tooting added: “I encourage people to protest, to demonstrate, to complain, to write into newspapers, to boycott certain goods - all lawful means open in a democratic society”.
A spokesperson for Sadiq Khan said: “This was a bad choice of phrase and Sadiq regrets using it.
“As Communities Minister at the time, Sadiq was talking about the need to engage with all parts of the community to tackle extremism and radicalisation - as he has pledged to do as Mayor.”
Tories insisted the words meant Mr Khan was unfit to be mayor.
Tory MP Nusrah Ghani said; “This language is totally unbefitting of someone seeking to become Mayor of London, and shows him to have poor judgement.
“He and the Labour Party should stop playing divisive politics, stop preaching and presuming so offensively, and show some respect to members of the public who, whatever their faith, can independently make up their own minds.”
Tory candidate Zac Goldsmith’s campaign has repeatedly pointed out Sadiq Khan’s links to extremists in the past, leading Labour to accuse him of fighting a racist ‘dog whistle’ campaign.