A Jewish former general secretary of Labour has resigned his membership, describing the party as “very plainly institutionally antisemitic.”

In a letter to Baroness Angela Smith, Labour leader in the House of Lords, Lord Triesman, who served as Labour’s general secretary from 2001 to 2003, described the party as “no longer a safe political environment for Jews or other opponents of antisemitism. It is time to recognise the reality.”

Lord Triesman was quickly followed by Lord Turnberg, who resigned the whip later on Tuesday. Lord Darzi of Denham also quit, citing antisemitism.

Lord Triesman first became a Labour member at 16, resigning in 1970 and joining the Communist party before returning to Labour six years later, where he had remained ever since.

He served as the general secretary of the Association of University Teachers trade union from 1993 until 2001.

The peer’s letter of resignation also described how “day by day the extent and depth of antisemitism becomes clearer in the top leadership and National Executive Committee.

"Antisemites are shielded, and solid and serious party members are thrown out unceremoniously. And each new manifestation is met by a grim parade of social media messages directed at Jewish party members.”

Born into a staunchly left-wing Jewish family in Tottenham, both of Lord Triesman's parents were Communists.

While at university, his involvement in a series of protests as part of the Radical Student Alliance led to MI5 opening a file on him.

In a 2002 interview with the JC, he described how, while growing up, "even the devout Communists in the family observed Rosh Hashanah and Yom Kippur." During 2008 and 2010 he served as chairman of the Football Association. 

His resignation from the party comes the day before an episode of BBC Panorama which is widely expected to reveal even more about Labour's antisemitism crisis when it is broadcast on Wednesday.

Lord Triesman also accused the party of having “slipped into the familiar gutter of so many of the hard left, and the old tropes about the secret wiring connecting Jewish entrepreneurs  and the use of wealth to exercise secret control can be heard on an almost daily basis.”

He stressed that for him this was not about Israel, saying that while a Shadow Spokesperson for Foreign and Commonwealth Affairs in the Lords between 2010 and 2014, he had “always criticised breaches of international law whatever the side, the Israeli government or those firing rockets at Israel and denying its right to exist.

“My decision is straightforwardly about the party leadership’s use of any excuse to allow their allies to attack Jews or engage with antisemites.”

Although Lord Triesman said he respected the decision of colleagues who felt they should “struggle on” within the party, he called the notion they should stay in the hope that something would improve a “unicorn delusion” and a “Mr Micawber option – that however unlikely, something is bound to turn up.

“I always said it was worth hanging on to fight so long as there was a prospect of winning. I now don’t believe with this leadership there is.”