An MP who led the revolt against anti-Semitism in Jeremy Corbyn’s Labour Party has been branded a ‘Jew whore’ who should burn ‘in the ovens’.

Joan Ryan, who quit Labour last month in protest at the party’s ‘culture of anti-Semitism’, called in police after receiving two separate death threats in the wake of her defection.

One was an unstamped handwritten note delivered to Ms Ryan’s Commons office on a week ago on Friday which branded her a ‘****-sucking, Jewish c*** who defected to Israel’ who should be raped and ‘set on fire’.

Joean Ryan, pictured left with former Tory MP Heidi Allen, right, has been forced to call the police after receiving two separate death threats from Jeremy Corbyn supporters angry at her criticism of the Labour leader and his handling of the party's anti-Semitism problem

Former Labour MP Luciana Berger, pictured, also quit Labour as a result of the vile anti-Semitic abuse she was subject to

The other letter, received at the MP’s constituency office in North London on the day before, said: ‘Stop telling lies about Jeremy Corbyn – he is a decent man, you lying Jew whore. You need to be shoved right back in the ovens.’

Ms Ryan has also passed to Scotland Yard the registration number of a black car that was parked near her constituency office with three men inside. She fears they were placing her under surveillance.

Ms Ryan, 63, is not Jewish but has been an outspoken critic of the party’s handling of the anti-Semitism crisis.

She left Labour last month to join the new Independent Group in protest at Mr Corbyn’s failure to tackle the issue.

The Enfield North MP last night spoke of her shock at the threats and her fears for the safety of her staff. She said she had decided to make public the full nature of the ‘disgusting’ threats to highlight what MPs who campaign against anti-Semitism have to face – whether or not they are Jewish.

Ms Ryan said last night that police had taken fingerprints from both letters, given her and her staff security advice and were investigating the ownership of the suspicious car, which a local trader had alerted her to.

Labour MP Chris WIlliamson, pictured, lost the whip last week after he suggested 'dark forces' were working against a party activist who criticised Jewish MP Rush Smeeth

Fellow Labour defector Luciana Berger revealed yesterday that a former Labour party member even made threats against the life of her unborn child after she joined The Independent Group.

Ms Ryan is also awaiting the results of a police examination of Commons CCTV to discover who managed to place another menacing hand-delivered card in her office last September. The chilling note mentioned her forthcoming visit to Cyprus – sparking fears that it was placed by someone with access to her private diary.

When she resigned from Labour, Ms Ryan accused Mr Corbyn of having ‘presided over a culture of anti-Semitism and hatred of Israel’ and said that she ‘could not be part of a party that allows racism to flourish’.

She said yesterday: ‘That people can send such filth-laden, disgusting messages is a shocking testament to how low our politics has now sunk. But the fact that some people think they can do so explains why many of us felt we had to quit the Labour Party last week.

‘My main concern now is for the safety of my staff who put in so much hard work in the constituency and in Parliament. However, we must never let up on the fight against the evil of anti-Semitism.’

The storm engulfing Labour deepened further after new remarks emerged from Corbynista MP Chris Williamson, who was suspended from the party last week for saying that Labour had ‘given too much ground’ to critics of its stance on anti-Semitism. Footage obtained by The Mail on Sunday shows Mr Williamson speaking of ‘dark forces’ working against a Labour activist who criticised Jewish MP Ruth Smeeth.

Mr Williamson was speaking at a meeting of Labour supporters backing Marc Wadsworth, who was expelled from the party last year after his confrontation with Ms Smeeth reduced her to tears.

Derby MP Mr Williamson said: ‘Some people might find it difficult showing solidarity with Marc, for fear of being implicated, criticised and demonised.

‘Well, I don’t give a s***. Certain dark forces are using their power, using their contacts in the media, in order to take out key allies like Marc and others from the struggle.’

Wadsworth had accused Smeeth of working ‘hand-in-hand’ with a reporter from the right-wing media to damage the Labour leader at the launch of a report on anti-Semitism in Labour. Speaking at the Justice4Marc event in Manchester, Mr Williamson insisted the anti-Semitism dispute had been ‘weaponised’ by enemies of Mr Corbyn.

He also claimed there was a witch-hunt of supporters of the Labour leader which echoed ‘George Orwell’s 1984, the Ministry of Truth’ and was similar to the actions of the East German Stasi.

During the meeting, one activist was loudly applauded after announcing she was suspended from Labour over anti-Semitism allegations but would not stop ‘speaking out’.

Another Labour councillor drew laughs with a series of comments in which she suggested the term ‘due process’ should be dubbed ‘Jew process’ and also swapped Labour’s ‘For the many not the few’ slogan to ‘For the many as well as bad for the Jews’.

The Mail on Sunday revealed last year that Jewish MPs were to be offered bodyguards at the Labour Party Conference due to fears about their safety.

Ms Berger was pictured arriving at the Liverpool conference accompanied by an armed police protection officer. She said at the time: ‘We are under attack. There are Jews in this country who do not feel safe.’

The Liverpool Wavertree MP joined The Independent Group in protest at Mr Corbyn’s lack of action over the anti-Semitic abuse she received, including from within her own constituency party.

A number of Labour MPs who had planned to follow Ms Ryan and Ms Berger out of the party have been urged to stay by deputy leader Tom Watson while he plots a new ‘party within a party’ that could undermine Jeremy Corbyn. They are said to include Dame Louise Ellman, who is on the brink of quitting over a ‘campaign of intimidation’ by pro-Corbyn party members.

The Metropolitan Police were unable to comment yesterday about the threats to Ms Ryan. Mr Williamson could not be reached for comment. Labour last night said: ‘We condemn anti-Semitism in all its forms.’