Zac Goldsmith’s attacks on Sadiq Khan have attracted the most media coverage of the London mayoral campaign so far. Khan has batted away accusations of associating with religious extremists thrown at him by his Conservative rival with dignity. The latest YouGov poll puts the Labour candidate on 48 per cent of first preference votes – 16 points ahead of his Tory counterpart and 20 points ahead after second preferences.

But Goldsmith is far from the only one slinging mud at Khan. George Galloway, the veteran left-winger who lost his Bradford West seat in the general election, has been trying to tap into socialism’s Indian summer, which delivered Jeremy Corbyn to the Labour leadership.

In many ways, he is a more impressive figure than Corbyn, even if he does not carry the all-important Labour label. He is better known, a better public speaker and the two share many of the same beliefs and the same reverence for Tony Benn. With the Liberal Democrats no longer a force in the capital, the Labour hard left more successful than ever and UKIP an irrelevance, Galloway could have expected a reasonable showing in this election; perhaps third place and a seat in the London Assembly.

He has brought his usual energy, fiery rhetoric and fury to the campaign trail but no one’s listening: he is currently polling at 0 per cent. Behind even Britain First leader Paul Golding, formerly of the British National Party.

According to Galloway, Khan is a New Labour stooge, too close to property developers and big business who has more in common with Goldsmith than Corbyn. Galloway has been endlessly retweeting people with “I voted for Corbyn” Twitter avatars assuring him that he is “real Labour” and has their vote, memes portraying Khan as Tony Blair in disguise, late pleas for a driver for his open top bus and trips on his open top bus to every rally and demonstration in London in a vain effort to drum up support for his bid for City Hall.

But, barring a handful of people who believe that Labour has always been too right wing, the message has fallen flat.

Galloway spent the best part of 30 years in the House of Commons, first as a Labour MP in Glasgow, then back in parliament in Bethnal Green and Bow and Bradford as a Respect MP, following his expulsion during the Iraq war. Those two victories were among the unlikeliest in parliamentary history. Divisive as he is – perhaps he is wilfully so – he is a remarkably successful politician, with one of the most recognisable faces and voices in Britain.