Labour peers could follow their Commons colleagues and quit over anti-Semitism, the party’s former general secretary has warned.

David Triesman, who served as general secretary from 2001 to 2003 and now sits in the Lords, told the New Statesman that some Labour members of the upper house were “profoundly unhappy” with Jeremy Corbyn’s response to this week’s split.

“These are very dark days for very long-standing and tribal Labour people,” he said. “We are no longer in a broad Party. Those days are gone for the foreseeable future.”

Accusing the leader of the opposition of ignoring those on the brink of leaving Labour, Triesman, who is Jewish, did not rule out quitting the party and said Corbyn had taken “the wrong decisions every time without fail” on anti-Semitism.

“It will not come as a surprise to you that a number of us are profoundly unhappy, especially with the inability of the Leader to do more than shrug his shoulders but otherwise ignore the people who feel we’ve reached an impasse,” he said.

Though critical of Labour’s economic policy and its approach to Brexit, he stressed that anti-Semitism was the issue most likely to provoke further departures. “Of course the position on Brexit is incompetent and our economic approach is highly problematic to deliver. I can readily imagine the case for fighting on inside the Party rather than leave it to the [Derek] Hattons of this world.”

“But the critical issue is the clear institutional anti-Semitism. Denying its existence but taking no action will leave anti racists including Jewish members feeling there is no future for us in the Party. It’s no longer each individual outrage. It's that the leadership takes the wrong decisions every time without fail. And in doing so they have made this country a less safe place. Whatever the rhetoric, they are midwives to a rapid drift to the extreme right.”

Asked whether he himself was considering leaving Labour, Triesman said: “There would have to be a sea change to lead me to believe Jews had a safe place in the party.”

“I was, as you know, General Secretary, and I know at first hand how rapidly it is possible to deal with disgraceful behaviour. So I can recognise systemic inaction when I see it.”

His comments mark a shift from his response to protests over the Labour leadership’s handling of anti-Semitism last April, when he told The Times he would stay in the party “because I think it’s a fight worth having.”

Accusing his party leader of ignoring the crisis within Labour, Triesman also suggested that those who claim accusations of anti-Semitism are mistaken for or conflated with criticism of the Israeli government were being disingenuous.

“I think all of those who say it’s all about the right to criticise Israel and in particular Netanyahu know perfectly well it isn’t,” he said. “The more frequent criticism is of people pulling the hidden wires of finance - the Rothschilds, George Soros, etc.”

“Europe heard this stuff in the 30s and we hear it today in Hungary. You root it out or you let it take hold. In Jeremy’s case he listens, shrugs his shoulders and says nothing.”