Labour has defended inviting a notorious Islamist preacher to appear at a party event, claiming that collaboration with “faith groups” is an “essential part of the fight against the scourge of racism”.

Shakeel Begg was listed as a speaker along with two of the party’s MPs, Janet Daby and Vicky Foxcroft at a Lewisham Labour Against Racism event Tuesday night, where activists discussed plans to “oppose Islamophobia and anti-Semitism”, “stop Tommy Robinson”, and to “challenge” government policies which make it harder for illegal immigrants to thrive in Britain.

An imam at the Lewisham Islamic Centre, which was attended by the terrorist killers of Fusilier Lee Rigby, Begg lost a libel case against the BBC in 2016 when a judge ruled he “clearly promotes and encourages violence in support of Islam and espouses a series of extremist Islamic positions”.

Begg had sought damages from the public broadcaster for describing him as an extremist during a Sunday Politics episode presented by Andrew Neil, who informed viewers that the Lewisham preacher had “hailed jihad as ‘the greatest of deeds’” while speaking at the East London Mosque.

According to Mr Justice Haddon-Cave, Begg is a “Jekyll and Hyde character” who “appears to present one face to the general, local and inter-faith community and another to particular Muslim and other receptive audiences”.

“The former face is benign, tolerant and ecumenical; the latter face is ideologically extreme and intolerant.,” he said of the imam, who according to the court documents “works closely with police … [as a member of] the Independent Advisory Group to Lewisham Police which advises the police on local issues, especially those relating to the Muslim community. He represents the LIC in the Safer Neighbourhood Team and the Hate Crime Working Group.”

Ahead of the meeting, which was reportedly attended by a large number of prominent south London Labour officials, anti-extremist experts had warned the party there would be “no excuse” for giving Begg a platform at the event given the imam’s history of extremist views.

“There is no debate to be had — Shakeel Begg was found in the High Court to be an Islamic extremist,” asserted the Henry Jackson Society’s Tom Wilson, adding: “There can be no excuse for any political party working with Begg.”

David Toube of the Quilliam anti-extremism think tank told The Sun that “the presence of a Labour MP on a platform which includes a cleric who has been found by a British court to be an extremist plays into the hands of anti-Muslim bigots.”

A spokesman for the party told the newspaper: “Communities and faith groups coming together is an essential part of the fight against the scourge of racism.”