An anti-fascist group has demanded that Baroness Tonge withdraws from a pro-Palestinian conference in December which is also due to be addressed by a far-right Hungarian Euro-MP.

The ‘Nothing British About the BNP’ group challenged the Liberal Democrat peer over the planned participation of Kristina Morvai, leader of the nationalist Jobbik party in the European Parliament.

But Nasim Ahmed, researcher for the Palestinian Return Centre, denied that Mrs Morvai was “among invited guests” and said it deplored her “extremist” party.

Maurice Cousins, of Nothing British, said that Mrs Morvai’s name appeared in a press release about the conference. This was published two weeks ago by the Palestine Telegraph newspaper and Wafa, the Palestinian Authority news agency.

Mr Cousins said: “To double check that some mistake wasn’t made, we spoke to her assistant Zsanett Makkai in the European Parliament, who confirmed that Mrs Morvai had been invited to attend.

“We were told that Mrs Morvai very much hopes to be at the December rally, diary commitments permitting.”

Mrs Morvai, whose Jobbik party was addressed last year by BNP leader Nick Griffin, was reported by Ha’aretz to have once said: “I would be glad if the so-called proud Hungarian Jews would go back to playing with their tiny little circumcised tail rather than vilifying me.”

But Mr Ahmed maintained: “We have sent a number of press releases with a list of our speakers and Christina is not among them. It appears there is a unified effort to sully this event.”

In a letter to Baroness Tonge on Tuesday, Mr Cousins also drew attention to the stated participation of Daud Abdullah, the deputy secretary general of the Muslim Council of Britain.

The Government suspended links with the MCB earlier this year after Mr Abdullah signed the hardline “Istanbul Declaration”, which called on any foreign warships sent to stop arms smuggling into Gaza to be “fought by all means”.

Baroness Tonge, whose outspoken attacks on Israel have led to complaints to the Lib Dems from the Board of Deputies, was unavailable for comment.

A spokesman for her party said: “Baroness Tonge is currently in Ethiopia working with the Bill Gates Foundation and is not contactable. We will speak to her about this event upon her return. We, of course, abhor the fascist views of the Jobbik party in Hungary.”