Jeremy Corbyn has been accused of keeping 'controversial company' after marchers on the May Day rally were seen carrying Stalin banners.

The Labour leader, thought to be the first in 50 years to address the event, insisted his party was 'absolutely against' anti-Semitism and other forms of racism.

But Tories said the presence of communist marchers bearing flags with images of the Soviet dictator and quotes would have given the Jewish community 'no comfort at all'.

Josef Stalin sent hundreds of thousands of citizens, many of them Jews, to the deadly Gulag prison camps.

Communists with banners featuring Soviet dictator Stalin were among marchers on the May Day rally

Mr Corbyn had been due to join the rally and speak at the end of the route in London's Trafalgar Square, but decided to make improptu address from a bus in Clerkenwell Green instead.

He argued that Labour's strength came from 'diversity', saying: 'We stand absolutely against anti-Semitism in any form.

‘We stand absolutely against racism in any form. We stand united as a Labour movement recognising our diversity.'

However, the Labour leader ignored questions from journalists about the crisis after his speech.

The intervention came as the anti-Semitism row escalated again with fresh warnings that Labour will be hammered by voters in elections this week for failing to deal with the issue.

Shadow Cabinet member Diane Abbott, a close ally of Mr Corbyn, risked further inflaming the situation by dismissing claims there is a problem as 'smears'.

Jeremy Corbyn addresses the May Day march in London

Unite boss Len McCluskey also waded in to accuse Blairite MPs of 'manipulating' anti-Semitism concerns in a bid to unseat the leader.

But Israeli Ambassador Mark Regev urged Mr Corbyn to disown extremist groups such as Hamas - which he previously described as 'friends' - as he warned that the party appeared to be 'in denial'.

Mr Corbyn is facing growing demands to eject close ally Ken Livingstone immediately after he again refused to apologise for claiming Hitler was a 'Zionist'. It has emerged that the disciplinary case against the veteran left-winger may not even get under way until July.

The leader's critics are planning a media blitz against him next weekend if Labour crashes in Thursday's council polls.

The sight of Communist Party marchers carrying Stalin banners among the trade unions and other workers' group raised fresh questions.

Tory MP Andrew Bridgen said: 'The fact that Jeremy Corbyn is keeping such controversial company at his left-wing parade will give the Jewish community no comfort whatsoever.

'It will reinforce the concerns that Mr Corbyn has associations with all the wrong people.'

Fellow Conservative backbencher Stewart Jackson said: 'He is so far from the mainstream of political life that it is bound to bring contagion to the Labour Party.'

'This is a contagion of extreme left views that is alienating people across the United Kingdom.'

Another Tory, David Morris, said the fact Mr Corbyn was at the same events as such groups was 'bonkers'.

'These are not the kind of people serious politicians associate with,' he said.

Shadow chancellor John McDonnell was previously ridiculed for quoting Chairman Mao at George Osborne across the Commons despatch box.

Mr McDonnell jokingly cited the notorious dictator's words before passing a copy of the infamous 'Little Red Book' to Mr Osborne. He later acknowledged that the joke had backfired to an extent.