Labour must expel immediately any member guilty of antisemitism to prove it is willing to “act against abuses”, Gordon Brown will say in a hard-hitting speech tomorrow.

The former Labour prime minister will pile pressure on Jeremy Corbyn to toughen party processes, also telling him he “owes the Jewish community an unqualified apology”.

His intervention follows the furore over the decision last week to readmit Chris Williamson – a strong supporter of Mr Corbyn – despite him saying Labour had been “too apologetic” about antisemitism.

The party is also braced for further criticism in a BBC Panorama episode entitled ‘Is Labour antisemitic?’ next week – and is still under investigation by the Equality and Human Rights Commission.

In his speech on Sunday, Mr Brown will call for a “radical change” of policy with automatic expulsion in any case where there is “irrefutable” evidence of antisemitism or another form of racism.

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

An expelled member should only have a right to appeal from outside the party and a Labour government should appoint a minister, backed up by an ambassador, to help with combating antisemitism across the globe.

“To the Jewish community, we promised ‘never again’,” Mr Brown will say, delivering the annual Isaiah Berlin lecture in London.

“We promised that the crimes of hatred, discrimination and persecution would never recur. We promised we would offer support and protection.

“But, at a time when attacks on Jewish schools have risen 100 per cent, attacks on or near Jewish synagogues 400 per cent and attacks are carried out on social media thousands of times over, we have not lived up to that promise.

“The Labour Party owes the Jewish community an unqualified apology. But that is only a starting point in rebuilding trust.”

The former prime minister, who left office in 2010, will urge Mr Corbyn to ensure Labour “call out antisemitism for what it is: racism, and, in this case, anti-Jewish racism”.

He will add: “Opposing antisemitism and every manifestation of racism goes to the heart of who we are and what we stand for as Labour.

“It’s about the moral soul of a party, whose most basic goal is a commitment to equality for all – not just for some who suffer oppression – but everyone.

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“To fail to act against the abuses we have witnessed runs counter to the very principles of the Labour Party we joined.”

Mr Brown will also call on Labour to prepare for government by drawing up a broad strategy, including better education in schools and stronger laws against racism in all its forms.

The decision to end the suspension of Mr Williamson was condemned as “unbelievable” and “turning a blind eye to Jew-hate” by Margaret Hodge, a Labour MP and campaigner against antisemitism in the party.