The Jewish Leadership Council has pleaded with Labour's shadow cabinet to "examine your consciences" over the party's antisemitism crisis, warning them "to be silent is to be complicit".

In a letter to all shadow ministers on Friday - ahead of a special meeting to discuss the crisis - JLC chair Jonathan Goldstein said the party "currently attracts antisemites and repels Jews. This is a sickening situation for you and for us, but it is the undeniable truth."

"In this situation, to be silent is to be complicit. To fail to lead is to allow evil to flourish," he said.

His letter was in stark contrast to a separate letter sent at the same time by Board of Deputies President Marie van der Zyl, which used far milder language and set out a programme of reforms the party should undertake.

Referring to the backlash against those who spoke to last week's Panorama about the party's Jew-hate crisis, Mr Goldstein wrote: "Whistle-blowers face legal action and “outriders” are set upon them. The phrase “a new, kinder gentler politics” has proven to be a hollow slogan...

"To our disgust, when we and others challenge and expose this problem, the reaction is more denial, more bullying, more falsehoods and more hatred against us, our community and those with the integrity to support us.

"Occasionally, the attacks come from in and around the Leader’s office, but it is also the constant function of social media activists and fake news sites that incite anger at a barely deniable arm’s length from the party leadership.

"It is a collective culture that attacks female Jewish Labour MPs, the Jewish Labour Movement and anybody deemed “Blairite” or “Zionist”. Now, as we have seen in such shocking terms, it is directly hurting your own party staff."

Mr Goldstein attacked dismissals of the problem, including claims it was the result of a surge in the number of members since Mr Corbyn became leader.

"The Labour Party’s antisemitism problem is cultural, not mathematical. Tackling it begins with tone and action, not denial and proclamation," he wrote.

"As members of the Shadow Cabinet, you now face a very difficult and unavoidable decision, in which inaction will signal your support for what has happened and what will follow.

"Please, do not under-estimate the importance of your actions for the future well-being of British Jews, or for the wider message that you give about racism, liberal democratic values and our British society."

In her letter, Mrs van der Zyl she singled out senior Labour staffers Seumas Milne and Karie Murphy - whom Panorama singled out for intervening in antisemitism cases.

She said they “shoulder a significant share of the blame” and “take personal responsibility for resolving this crisis”.

She wrote: "We urge you to take this opportunity to turn the tide. The alternative is to leave Labour permanently damaged as an institutionally racist party. Our community and our country will not forgive any further failure.”

She set out actions the party should take, including ensuring MPs and councillors did not share platforms with those suspended or expelled by the party over antisemitism, doing more to promote the IHRA definition of antisemitism and a fixed timescale for dealing with complaints of racism against members.