More than 60 Labour peers have taken out an extraordinary newspaper advertisement, accusing Jeremy Corbyn of failing the “test of leadership” as the row over antisemitism in the party’s ranks rages on.

Claiming Mr Corbyn has been unable to defend Labour’s ”anti-racist values”, the members of the House of Lords warn the party is no longer a “safe place”.

“The Labour Party welcomes everyone* irrespective or race, creed, gender identity, or sexual orientation (*except, it seems, Jews),” the peers write. “This is your legacy, Mr Corbyn.”

The fullpage advertisement, published in The Guardian, is scathing of Mr Corbyn’s leadership of the Labour Party, claiming he has prompted the resignation of “thousands” of members due to a “toxic culture you have allowed to divide our movement”.

It continues: “After initially defending the racist mural in east London you admitted being unable to recognise that it was antisemitic because you didn’t look closely enough.”

Protests against Labour antisemitism Show all 14 1 /14 Protests against Labour antisemitism Protests against Labour antisemitism Protesters clashed during the demonstration Reuters Protests against Labour antisemitism Members of the Jewish community hold a protest against Labour party leader Jeremy Corbyn and antisemitism in the Labour Party AFP/Getty Protests against Labour antisemitism Protesters hold placards and flags during a demonstration, organised by the British Board of Jewish Deputies for those who oppose antisemitism, in Parliament Square Reuters Protests against Labour antisemitism Hundreds of people gathered in Parliament Square to protest against antisemitism in the Labour Party EPA Protests against Labour antisemitism Labour MP Luciana Berger speaks during the protest PA Protests against Labour antisemitism A protester blows through a shofar during the demonstration Getty Protests against Labour antisemitism Members of London's Jewish community protest in support of Labour leader Jeremy Corbyn outside parliament EPA Protests against Labour antisemitism Labour MP John Mann speaks during a protest against antisemitism PA Protests against Labour antisemitism People protest against antisemitism in the Labour Party as Jewish community leaders have launched a scathing attack on Jeremy Corbyn, claiming he has sided with antisemites ‘again and again’ PA Protests against Labour antisemitism Labour politicians Stella Creasy and Chuka Umunna leave after attending the demonstration Getty Protests against Labour antisemitism A pro-Jeremy Corbyn protester holds a placard during a counter-protest Getty Protests against Labour antisemitism A support of the Labour Party hold up a placard during the demonstration Reuters Protests against Labour antisemitism Jeremy Corbyn supporters during the demo Reuters Protests against Labour antisemitism A protester holds up a sign reading ‘For the many, not the Jew’ AFP

The advertisement, supported in total by 64 peers including the former general secretary Iain McNicol, Peter Hain, and Beverly Hughes, follows backlash over the way Labour has handled cases of alleged antisemitism in the wake of a BBC Panorama documentary aired last week.

The programme featured several whistleblowers claiming Mr Corbyn’s team had intervened in the disciplinary process – a claim denied by the party officials, who have complained to the BBC about the Panorama investigation.

The peers also accuse Mr Corbyn of not having “opened (his) eyes” or “accepted responsibility” for the row which has engulfed the party.

“We can’t be a credible alternative government that will bring the country together if we can’t get our own house in order,” the advert says.

“Your failure to do the right thing will lead to the failure of the Labour Party being able to make our country a better place for the people and communities we seek to serve.”

“You have failed to defend our party’s anti-racist values,” it adds. “You have therefore failed the test of leadership.”

Peers’ advert in The Guardian newspaper published on Wednesday

Responding to the advert published on Wednesday, a Labour Party spokesperson said Mr Corbyn “stands in solidarity with Jewish people”, adding: “Regardless of false and misleading claims about the party by those hostile to Jeremy Corbyn’s politics, Labour is taking decisive action against antisemitism.

They added: “Jeremy Corbyn has made clear in interviews, videos and and articles that there is no place for antisemitism in the party.