An extremist who claims he is a friend of Labour leadership candidate Jeremy Corbyn once blamed the JC for being banned from Britain .

Dyab Abou Jahjah, a former Hizbollah fighter and leader of a radical Muslim group, had addressed two meetings in London in March 2009 – one while sitting alongside Mr Corbyn in Parliament.

But the Lebanon-born activist was detained by immigration officials for six hours when he attempted to return to Britain a week later.

On his blog he wrote: “They say I am a threat to the peaceful co-existence of communities.

“It is funny they only discovered that after my successful visit... and after granting me access a few days ago.

“I think it all has mainly to do with the lobbying of the Zionists who again have a hate article full of lies on me in today’s [April 3] issue of the Jewish Chronicle. ”

The JC had featured the news that the then Board of Deputies president Henry Grunwald QC had written to the Home Secretary of the time, Jacqui Smith, to raise concerns about Jahjah’s presence in Britain .

Jahjah was jailed in Belgium for fomenting violence in 2002 when Muslims rioted after the murder of a Moroccan teacher.

In 2007 he caused outrage when he claimed to have published a picture of Anne Frank in bed with Adolf Hitler alongside the caption “put this in your diary, Anne”.

He has also reportedly questioned the existence of gas chambers during the Holocaust, said he considers the death of every Dutch, British and American soldier a “victory”, and claimed gay people are “Aids spreading fagots”.

A fortnight ago Jahjah posted a tweet calling Mr Corbyn a “friend”. The frontrunner in the Labour contest had hosted him at the launch of a British branch of the International Union of Parliamentarians for Palestine.

In a blog posted on Wednesday, Jahjah denied being antisemitic. He said he had "met and collaborated" with Mr Corbyn in 2009.

He wrote that following the visit to Britain "the pro-Israel lobby then woke up and started a smear campaign against me resulting in a hasty and unjustified decision by the interior minister to deny me re-entry to the UK.

"That campaign had almost the same content of the current campaign that is spearheaded by the pro-Israel lobby and the conservatives. The claims are that I am antisemitic, that I am a bigot, and that I rejoice the death of British soldiers."

Jahjah said he was "opposed to Zionism and to the policies of the state of Israel. I am indeed a supporter of a one secular state for all solution in Palestine in the line of the south African dismantling of the apartheid state.

"I do not support ethnic-religious colonial states, whether they are Jewish, Muslim or Buddhist. Therefore, all the supporter of the ethnic-religious colonial state of Israel have all the reasons to express their horror of my position.

"However, when they accuse me of antisemitism because of that they have no ground to stand on. Equating Zionism with Judaism is what they do in this case, and that itself is antisemitic."

In reference to his past comments about the deaths of British soldiers, Jahjah added: "Every soldier taking part in an illegal occupation is a legitimate target for resistance."