The Labour party owes the Jewish community an unqualified apology. But that is only a starting point in rebuilding the trust that has been shattered.

A few months ago, I joined hundreds of other non-Jewish Labour party members in signing up as an affiliated member of the Jewish Labour Movement (JLM). Instead of Jewish members leaving Labour, Labour members joined the Jewish community.

Last September many took heart when the Labour party formally adopted the International Holocaust Remembrance Alliance definition of antisemitism. But it was a false dawn. In the ensuing months, it became clear that such a change in policy could never be enough. And just when you think that things cannot get worse, they do.

Words will not be enough: we need a radical change of policy to change the whole culture of our movement

For somewhere along the way it became possible for a Labour MP, close to the leader, to suggest that in dealing with antisemitism we were being “too apologetic”. As if the real issue was not the sheer volume of uninvestigated incidents – which clearly required an apology – and what I call “the web of poison”, with some members of the Labour party (largely via Twitter, Facebook and other social media) spreading and normalising messages that seek to justify and propagate a centuries-old antisemitism. These messages are not appearing by accident: they are specifically designed by antisemites to lure people into targeting and demonising the Jewish people as a whole.

Of course, this poison is not restricted to the Jewish community or to Labour. Islamophobes who use social media to condemn all Muslims also exhibit a racism that disfigures more and more of our society – especially now that a populist nationalism, which needs enemies, is on the rise.

Antisemitism takes many forms, both ancient and modern. Legitimate criticism of the actions of the government of Israel is sometimes exploited to promote the age-old vilification of the entire Jewish community. And there are despicable attempts to allege a Jewish-capitalist conspiracy – a revival of the discredited and darkest antisemitic creeds of the past.

We cannot go on ignoring the consequences of the upsurge in hate and hate speech. A UK Jewish community of just 300,000 – already suffering from a record number of antisemitic incidents, including attacks on synagogues and Jewish schools – is now facing a massive increase in online abuse, all too often in the form of sinister, anonymous and untraceable internet trolling.

No individual or community should be treated in this way. We have to call out antisemitism for what it is: racism. In this case, anti-Jewish racism. Even the suggestion that the Labour party is in any way silent, ambiguous or ambivalent in its response to such a toxic environment shames us all. Because opposing antisemitism and every manifestation of racism goes to the heart of who we are and what we stand for as Labour members. 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 for everyone.

To fail to act, even against a single case of abuse, means we are not living up to the principles of the Labour party we joined. And so it’s now time for our leadership, the national executive committee (NEC) and Labour conference to face up to the scale of a problem we have, for far too long, failed to address. Much as we might like to, we cannot now turn the clock back or undo the hurt that has been caused. Nor can we erase the memory of the damage done. Words will not be enough: we need a radical change of policy, starting at our September conference, not just to eliminate antisemitism but to change the whole culture of our movement. Automatic expulsion is the procedure we adopt when members vote for or support other political parties. When the offence is as counter to our core principles as antisemitism, we cannot, in all conscience, be less demanding and less immediate in our response. We should automatically expel – and not just suspend – in cases where there is irrefutable evidence of antisemitism or any kind of racism.

Of course, we should ensure the right to an appeal, but the appeal system has to be independent of the Labour party’s hierarchy, with members chosen for their standing and integrity among the public – and after consultation with the Jewish and other communities.

And while I gave the go-ahead under the last Labour government for the establishment of a post-Holocaust envoy, it is now clear we need to go much further. The next Labour government should announce it will appoint a designated minister, backed up by an ambassador. This role should be to combat antisemitism – by monitoring and reporting on its evil presence and pressurising governments everywhere to eradicate it.

When, in 2016, the Equality and Human Rights Commission reviewed 50 years of anti-racist legislation and enforcement, it called on the government to formulate a comprehensive anti-racism strategy fit for new times. The need is more urgent now and, in preparation for the next Labour government, we should consult on a new and broader strategy that begins with better education in our schools – for example, we should do more to support the work of the Holocaust Educational Trust – and include stronger laws against racism in all its forms.

Some will suggest that focusing time and effort on fighting antisemitism is a diversion from the task of persuading people of the merits of the party’s progressive economic and social philosophy.

But standing up to racism is not a distraction from, or obstacle to, the realisation of our egalitarian ideals. It is, in fact, the most fundamental expression of them: a challenge far greater than simply talking about a fairer world for those suffering injustice – striving ceaselessly and unequivocally to realise that ideal.

• Gordon Brown was UK prime minister from 2007 to 2010. He will deliver the 17th annual Isaiah Berlin Lecture on Sunday in London

• This article was amended on 10 July 2019 because an earlier version misnamed the Equality and Human Rights Commission as the Equalities and Human Rights Commission. This has been corrected.