Senior figures who want to “batter” pro-Israel voices in politics; volunteers who promote antisemitic conspiracy theories; activists who compare the plight of Palestinians to the treatment of Jews by the Nazis in the Holocaust.

Throw into the mix prominent MPs, the leader of the National Union of Students and a senior police officer, and it is little wonder that last week’s event in Parliament organised by the Muslim Engagement and Development (Mend) group caused such shock and anger.

Mend describes itself as a team of “entrepreneurs, doctors, policy analysts, grassroots activists, Muslims and non-Muslims all bound by the ethos of a zero-tolerance policy towards anti-Muslim hatred”.

But for years it has been a notorious presence in public affairs spheres in Westminster and beyond.

Jewish groups this week said they had long-standing concerns about Mend’s “political threat” because, according to one leading figure, “of the narratives they promote and attitudes they encourage”.

One expert said Mend was regarded as a “problematic organisation” because it appeared to encourage Jews and Muslims to oppose each other rather than to work together to tackle racism and extremism. There are other partners in the Muslim community who we think are more genuine and reliable in their opposition to antisemitism and extremism,” said one source.

None of that stopped Jeremy Corbyn and a series of Labour MPs speaking at the Portcullis House event last week. Mr Corbyn told the audience at the Islamophobia Awareness Month launch: “Our future lies in mutual respect between all communities.”

A video made by Mend to coincide with the campaign features Mr Corbyn, Liberal Democrat leader Sir Vince Cable and Baroness Warsi, former Conservative chair.

After the JC asked about Sir Vince’s decision to appear in the video, a Lib Dem spokesman said that, when the filming took place, he wanted “to raise awareness of the important issue of anti-Islamophobia and was not aware of the serious allegations of antisemitism surrounding a number of their staff and volunteers”.

Mr Corbyn’s office did not respond to requests for a comment about his appearance in the video.

The appearance of the Labour leader at the Mend event sparked one senior Jewish communal figure to ponder: “It begs the question that, if he becomes Prime Minister, who are his main Muslim community contacts? It’s alarming to see him endorsing Mend.”

Jennifer Gerber, director of Labour Friends of Israel, said it was “utterly unacceptable” that Mr Corbyn “chose to attend an event organised by a group which has repeatedly peddled myths about the power of the ‘Israeli lobby’ that play into classic antisemitic tropes”.

One source familiar with the Muslim community said there was “real concern” that the group had been “given a veneer of respectability” thanks to the appearance of prominent figures at the session. “These politicians have legitimised Mend and their xenophobic, poisonous version of Islam,” the source added.

The attendance of Chief Superintendent Dave Stringer, head of community engagement for the Metropolitan Police, at Mend’s event also sparked concerns among moderate Muslim groups.

The JC understands that Chief Supt Stringer decided to attend at the last minute in order to ensure the Met was seen to be involved in efforts to combat Islamophobia in the capital.

But the explanations from the senior officer, and from the Lib Dem leader, are weakened by the amount of coverage afforded to Mend in recent years.

The day before the Westminster event last week, the Henry Jackson Society think tank published an 87-page report highlighting a series of concerns about Mend’s work, staff and volunteers.

It said the group was “Islamists masquerading as civil libertarians” and that it had attacked liberal Muslims engaged in counter-extremism.

On occasions, officials and volunteers “have expressed a variety of troubling views on terrorism”.

Less than a year ago, the Board of Deputies told a parliamentary select committee inquiry into hate crimes that Mend’s approach “risks increasing hostility and suspicion between the Jewish and Muslim communities”.

The assertion provided by the Board was predicated on years of examples — from the claim of its founder, Sufyan Ismail, who described Mend’s work as being to “batter the Israel lobby”, to regional volunteers with overactive social media accounts.

Mr Ismail and Mend last week admitted that the use of the word “batter” was “perhaps a poor choice” that could have been misinterpreted “as having connotations of physical violence. Thus, with the benefit of hindsight, a better word would have been ‘defeat’”.

Mend told the JC this week that it “categorically rejects all accusations of homophobia and antisemitism”.

In a previous incarnation, Mend was known as iEngage. When the All Party Parliamentary Group on Islamophobia was set up in 2011, MPs intended to use iEngage to provide administrative support, but that plan was dropped after the Community Security Trust described the group as having “a troubling attitude to antisemitism”. Since rebranding, Mend has worked hard to establish itself on the political scene, running fringe events at party conferences with high-profile speakers and developing voting strategies for Muslim communities at elections.

In April, it appointed Islamist Azad Ali as its national community head. He previously lost a libel case against newspapers that reported he was a hardline activist who had suggested Iraqi Muslims were justified in killing British and American soldiers.

On his own blog, Mr Ali denies calling for the killing of British soldiers and says his position on Hamas and other issues had been misrepresented in attempts to “smear” him.

Mend said Mr Ali was on record stating he “has never called for — and never will call for — attacks against British soldiers”.

In a lengthy response to criticism last week, the group said on its website: “We have worked with many Jewish and homosexual MPs over the years and continue to do so.”

The group said one accusation that it had boycotted a Holocaust Memorial Day event was “entirely untrue” and that it was considering legal action.

Wes Streeting, Labour’s Ilford North MP, who was criticised last week over his plan to attend the Parliamentary event, used his appearance to warn Mend that its work in combating Islamophobia would be “fatally undermined if the organisation tolerates, or is perceived to tolerate, individuals expressing attitudes that fall far short of Mend’s stated commitment to creating a more inclusive and tolerant Britain”.

He added that behaviour such as reported remarks about gay people and the use of antisemitic tropes to criticise the state of Israel “cannot be excused or tolerated.”

But all too often, such behaviour and actions are tolerated.

Siema Iqbal, a GP in north Manchester and chair of Mend’s working group in the city, retweeted a message during the 2014 Gaza conflict which read: “Truce in Gaza? Don’t you believe it! The Jews are shopping around for cheap bombs.”

Sahar Al-Faifi, Mend’s South Wales and West England regional manager, and a respected molecular scientist, wrote on social media after the London Bridge terror attack carried out by Islamists days before June’s general election, asking “who is to blame?”.

Referring to “pro-Zionists pro-war individuals such as Robert Rosenkranz, Lord Ashcroft and Lord Kalms the owner of Dixons”, she wrote: “These people make money from wars and it is within their interest to make the world unstable by funding fear via morons and militias.”

One regional Mend activist, Sulayman Munir, has repeatedly used social media to compare the situation in Gaza to the Holocaust, publishing Nazi concentration camp images next to those of Palestinians.

Mend said the comments by Ms Al-Faifi and Mr Munir were “an internal matter” and had been addressed.

In Leeds, a Mend volunteer last month gave flowers in a show of solidarity to a city synagogue which had been daubed with antisemitic graffiti. Mend tweeted a news story about the gesture alongside the hashtag #strongertogether.

The JC understands that, even so, the Community Security Trust was alerted because of fears of a security risk.