Shadow Foreign Secretary Emily Thornberry has said it was wrong for Labour to “go for” former officials who blew the whistle on anti-Semitism in the party.

Ms Thornberry said they should be addressing the issues raised in last week’s BBC Panorama programme, rather than attacking ex-staff who spoke out about what was happening in the party.

Labour continues to complain about the documentary, which claimed that senior figures – including Jeremy Corbyn’s communications chief Seumas Milne and general secretary Jennie Formby – had interfered in anti-Semitism investigations.

Jeremy Corbyn said the Panorama documentary contained 'many, many inaccuracies.' Credit: PA

Responding to Ms Thonrberry's comments, Mr Corbyn said: "Anti-Semitism is a poison within our society, and as a party we have a process for dealing with it and we support all our staff for any stress that they're going through and dealing with."

Pressed on whether he supports her comments, he added: "Emily is speaking for the party, has made her views known, and obviously we are dealing with this process."

Quizzed on what it would take for him and Labour to admit there is a problem with anti-Semitism within the party, Mr Corbyn said: "There's a problem with anti-Semitism within our society, there's a problem with racism in our society, and our party does not tolerate racism in any form whatsoever.

"And we take action against anyone committing any racist act whatsoever in our party."

However, in an interview with BBC One’s The Andrew Marr Show on Sunday, Ms Thornberry said the party needs to face up to the fact that it still has a problem with anti-Semitism.

“I think that we shouldn’t be going for the messengers, we should be looking at the message. I think that is what is important,” she said.

“Nobody can pretend that there isn’t an ongoing problem within the Labour Party about anti-Semitism, about our processes for dealing with it.”

However, shadow chancellor John McDonnell insisted the problem was being dealt with, with new systems put in place.

“There’s always lessons to be learnt, but I think the way Jennie Formby, our general secretary, has operated, implemented the measures, is getting on top of this,” he told BBC Radio 4’s World At One.

Ms Thornberry also criticised deputy leader Tom Watson for attacking Ms Formby while she was undergoing treatment for cancer.

“I wish he wasn’t attacking somebody who is going through chemotherapy. I think that is a mistake,” she said.

“She is the general secretary of the Labour Party but we know that she is very ill. I think it is completely inappropriate to personalise this.”

Her comments followed a bitter tirade from Unite union general secretary Len McCluskey, who said Mr Watson “and his pals” should "well be ashamed of yourselves”.

To cheers from the crowd at Durham Racecourse, he declared: “Jennie, our message to you is that the Durham Miners’ Gala stands with you.”

Len McCluskey used his address at the Durham Miners’ Gala to criticise Tom Watson. Credit: Owen Humphreys/PA

Meanwhile, it emerged that two of the former officials interviewed by Panorama said they were now going to sue the party.

Sam Matthews and Louise Withers Green said they believed they had been defamed by Labour in its response to their allegations.

Labour said the claims had come from “disaffected former officials” opposed to Mr Corbyn’s leadership who had “personal and political axes to grind” casting doubt on their “credibility” as sources.

Mark Lewis, the prominent media lawyer who is acting for the pair, told The Observer: “These are very serious libels. Those representing the Labour Party have acted in a way that set out to destroy the reputations of the whistleblowers.

“In their effort to destroy these people, they have left it for the courts to decide who is telling the truth. It is ironic that the bosses at the workers’ party have decided to go against the workers.”