Britain’s two largest Jewish groups are calling on Jeremy Corbyn to protect MPs who attended a protest against antisemitism in his party, before their meeting with the Labour leader later this month.

Some of the Labour MPs who attended the demonstration three weeks ago faced a backlash from the left of the party. One MP faced a local motion of condemnation, although it was eventually defeated.

Writing in the Observer, Jonathan Goldstein, chair of the Jewish Leadership Council, and Jonathan Arkush, president of the Board of Deputies of British Jews, said that the Labour MPs who attended the protest needed the leader’s support as part of the fight against antisemitism.

“Courageous Labour MPs spoke with great pain, honesty and integrity about the problem,” they write. “We knew, as did most of the crowd, the huge risk that these MPs were taking for being there. It is these MPs and many other councillors and members who are now the most vital opponents of antisemitism.

“Inevitably, the MPs are facing a perverse backlash for opposing antisemitism and for caring about their party. Corbyn’s leadership in defence of them will now be a crucial component of his promised commitment to combating antisemitism.”

The two groups said they acted after a series of allegations of antisemitism by Labour members. The party is facing a backlog of disciplinary cases. The groups have agreed to a meeting with Corbyn on 24 April and said they would use it to ask him to deal with “issues of leadership, of education, ensuring an effective, transparent and just disciplinary process and tackling a culture of ‘victim-blaming’ that has severely compounded matters.

“Last month’s protest was a necessary moment of catharsis, as painful for Labour as it was for our community, but we cannot now return to ‘business as usual’. We need this to be a genuine turning point and will do everything we can to make it so. We can achieve this together if Corbyn can fulfil his pledge to be our “militant ally” in the fight against antisemitism and demonstrate his understanding that what is now needed is firm action and not just words.”

Corbyn has vowed to tackle antisemitism and has apologised for appearing to defend a mural that he has subsequently acknowledged to have been antisemitic. A recent survey by Deltapoll found that 51% of voters believe Labour has a problem with antisemitism to some degree. It found 17% think it is “riddled” with people holding antisemitic views, including Corbyn. The same proportion think “pockets” of antisemitism exist within Labour, including its leader. Two-fifths of 2017 Labour voters (39%) think that people within the party hold antisemitic views.

A Labour spokeswoman said: “There is absolutely no place in our party or our movement for antisemitism. Jeremy has repeatedly made this clear. Jeremy has asked Jennie Formby, Labour’s new general secretary, to make rooting out antisemitism her number one priority.”