Chris Williamson's signature remained on pro-Gilad Atzmon petition for hours

While a complete list of signatories is only available to those who started a petition, the JC saw the page was still promoting Mr Williamson's signature more than three hours after he had tweeted to promote it.

It is unclear whether he has now removed his signature, as all signatories are offered the chance to do in an automated email Change.org sends them when they sign something.

Mr Williamson did not respond to request for comment.

The petition called on Islington Council to overturn its ban on Mr Atzmon performing with his band The Blockheads at a council venue.

Mr Atzmon has blamed the Grenfell fire ton "Jerusalemites” and has also been accused of posting antisemitic tweets, including one which appeared to endorse an “Anne Frank Halloween costume”, and another in which he said “I despise the Jew in me and detest the Jew in you”.