Jeremy Corbyn claimed that Islamic State was 'not a great threat to the UK' only hours after a video of Jihadi John beheading a British aid worker horrified the world, The Mail on Sunday can reveal.

Mr Corbyn made the extraordinary statement at a Stop The War Coalition rally on October 4, 2014, following the release of footage the day before showing the sickening murder of father-of-two Alan Henning.

The Salford taxi driver had volunteered as an aid worker and travelled to Syria in 2013. But soon after arriving he was kidnapped by Islamic State fighters and held hostage.

Jeremy Corbyn claimed that Islamic State was 'not a great threat to the UK' only hours after a video of Jihadi John beheading a British aid worker horrified the world

Nearly a year later, the video was released by IS showing his execution by Mohammed Emwazi, nicknamed Jihadi John – after John Lennon – because he was in a four-man British IS cell dubbed The Beatles.

The footage repulsed the world and made Emwazi the world's most wanted man. Prime Minister David Cameron issued a 'kill or capture' order and Emwazi was killed in a joint US-British drone strike on November 12, 2015.

Mr Corbyn addressed the murder of Mr Henning at the hard-Left Stop The War Coalition rally in Central London and blamed 'jingoism' and Britain's foreign policy rather than IS.

'We have to remember that the price of war, the price of intervention, the price of jingoism, is somebody else's son, and somebody else's daughter, being killed,' he said.

Speaking to the Turkish-based Anadolu news agency after his speech, Mr Corbyn said: 'I think ISIL [Islamic State] is not a great threat to the UK. I think the bigger threat to the UK is our continuing involvement in wars all around the world.'

At the time, IS controlled territory roughly the size of the UK across Iraq and Syria and boasted more than 900 British recruits.

Last night, when contacted by this newspaper, Labour did not distance itself from Mr Corbyn's comments and instead drew attention to his speech last week when he claimed he had been correct when he opposed the Iraq war.

Critics of Mr Corbyn (pictured) claim that he is unfit to be Prime Minister

But critics said Mr Corbyn was unfit to be Prime Minister.

Former Labour Minister Ian Austin said the MoS revelation was 'the most powerful example yet of the way that Jeremy Corbyn takes the side of this country's enemies, not our own people'.

He added: 'Corbyn does not take the terrorist threat seriously, believing it is caused by the West – not by people who murdered hero Alan Henning. He was an ordinary guy doing his best to help the Syrian people.'

He also claimed that rather than criticise 'the brutal Syrian regime, whose barbaric attacks on their own people caused millions to flee and are responsible for hundreds and thousands of deaths', Mr Corbyn 'laid into Britain instead'.

Mr Austin, chairman of anti-extremism group Main Stream UK, which unearthed Mr Corbyn's comments, added: 'I'm not afraid to admit it – the idea of a Corbyn government makes me scared.

'He's not fit to lead the Labour Party and not fit to be Prime Minister. That's why me and millions of other lifelong Labour voters will vote to keep him out this Thursday.'

Mr Corbyn sparked uproar by attacking the killing of IS leader Abu Bakr al-Baghdadi in Syria on October 26 by US special forces, claiming that it would have been right to arrest him, despite the fact he blew himself up with a suicide belt.

He also claimed that IS bride Shamima Begum should be allowed to return to Britain and once claimed the death of 9/11 mastermind Osama bin Laden was a 'tragedy'.