The former businessman, who is Jewish, attacked Labour’s leadership as the party reels from fresh claims about its handling of antisemitism allegations.
The Jewish Labour Movement – which has been a formal affiliate of the party since 1920 – told Sky News that 30 whistleblowers have come forward to detail their experiences of Labour’s management of anti-Jewish hate claims.
It follows a BBC Panorama documentary in which former Labour officials claimed they were undermined in their efforts to tackle antisemitism – something the party has denied.
Labour is also facing an investigation by the Equalities and Human Rights Commission (EHRC) over the issue, with Lord Levy claiming the party’s leadership will have to “answer” to the watchdog.
The peer set a deadline of the end of the year, when he understands the EHRC will release its findings, to make a decision on his future in the party – despite admitting it will not be easy to stay in the party.
He said: “I put myself under the microscope every day to have to think ‘do I want to stay in this party’.”
In the meantime, Lord Levy vowed not to follow three of his fellow peers – Lord Triesman, Lord Darzi and Lord Turnberg – who this week resigned the Labour whip.
Responding to the Panorama programme, he added: “When you hear eight young members of staff and party members talking about suicide attempts, talking about breakdowns and anxiety, frankly that’s every reason to still stay in this party.
“To fight and to see if we can get this party back to the party I came into many, many years ago, that I believe in and whose values I still believe in.
“Not the values of the current leadership and what they’re allowing to happen.
“We have to change things. If you go out from the party, just the odd one here and there or the odd two and three, what are you going to achieve?”
Expanding on his decision to not yet leave Labour, and his determination to try and bring about change, Lord Levy suggested current leader Jeremy Corbyn and his close circle would not always remain in control of the party.
He said: “We may not be successful and if we are not successful, then I will do the same, I will leave the party.
“But why walk away? These people believe and seem to think they will control this party forever.
“I don’t think that’s the reality, I don’t think that will happen.”
Lord Levy, a former personal envoy and special adviser on the Middle East to Tony Blair, suggested shadow cabinet figures such as deputy leader Tom Watson and shadow Brexit secretary Sir Keir Starmer would “endorse” his position.
Mr Corbyn himself has not commented publicly since the publication of the latest claims about the party’s handling of antisemitism allegations.
And Lord Levy asked: “Why isn’t he standing up? Why isn’t he leading? Why doesn’t he feel shame at these young party staff, party members, in the state they’re in?
“Thinking of committing suicide, anxiety. Why is he not standing up there and answering to these allegations?”
A Labour spokesman has criticised the Panorama programme, saying it “engaged in deliberate and malicious representations designed to mislead the public”.
They added that the officials who spoke to the BBC were “disaffected” individuals who have “both personal and political axes to grind”.
Labour has submitted a written complaint to the BBC.