Look at the sheer weight of the examples of antisemitic attitudes, Facebook posts, and behaviour across so many different levels of the party and so many different parts of the country.
There are hundreds and hundreds of examples. Anyone who says there is no evidence either hasn't looked or is deliberately closing their eyes.
We've also seen that the party structure, the party machine and the party leadership, have not dealt with these cases properly - firstly, not really recognising that there was a problem, and more recently we've seen evidence of the obstruction of disciplinary processes.
Speak to Jewish party members. Look at their personal experiences, and the number who have left because of experiences that happened to them because they are Jewish. Put all that together, and it's a compelling case.
We've argued for a focus on debate and education - which is not the same as "training". But many talk about it only in terms of how many expulsions there should be.
It's necessary to have the disciplinary process working properly, but that can't really address the culture behind the antisemitism. That definitely needs political education. And it's not like health-and-safety training, or something.
The party, having promised that they would have a whole programme of education, haven't done it, and they've obstructed the Jewish Labour Movement's attempts to have education or training or whatever they call it.
At the heart of it is a pattern of attitudes in how too many people on the left and in the Labour Party relate to Jews, antisemitism, Israel, and the Holocaust
You've commented on it being a problem that many people see modern antisemitism only in terms of traditional models of racism.
A lot of people on the left, when they think about racism, think about structural racism and discrimination and exclusion which restrict people's access to education, housing, income, employment, health.
Post-war, that concern has been focused on minorities from former British colonies who have come to Britain. Antisemitism operates in different ways.
Modern antisemitism does not operate by excluding Jewish people from areas of society. It operates through conspiracy theories, through myths, through scapegoating, through the demonic image of the all-powerful Jew, or nowadays, often, of the all-powerful Zionist. Part of that is the homogenising of Jews into a stereotype as being white and wealthy and powerful, and, globally, of Israel being part of the American-led western power structure. So on the left you often get, at best, an inability to see antisemitism as what it is, or to see Jewish people as they are.
It is very rare to find Jews included in BAME structures on the left. Jews are not thought of as an ethnic minority. And yet a lot of Jewish people consider their Jewishness to be an ethnicity, especially those Jewish people who are not religious believers.
The inability to recognise and understand antisemitism as it actually operates, unless it comes packaged as fascism, is connected to an inability to understand Jewish people as they actually are.
But isn't it true that Israel is a very close ally of the USA, and has been since 1967? It is. But you get an interpretation of world events which sees everything bad as down to western imperialism, and then supporters of Israel as supporters of that global network of power and oppression and racism.
Then the fact that the overwhelming majority of Jewish people, in Britain say, feel a strong emotional, personal, familial bond to Israel - even before you get onto their political views - places them under suspicion. The most prominent leaders of the drive to define away antisemitism in the Labour Party are Jewish Labour Party members who are very vocal about defining themselves as Jewish. That's a very old Jewish politics. It's a family argument, really. There is a small number of Jewish anti-Zionists who are very vocal in promoting their opposition to Israel - often not only to what it does, but to its existence. Importantly, their politics incorporates opposition to the mainstream of the Jewish community as well as to Israel.
They turn to the broader left to get an audience and support, and they hitch part of the left onto their anti-Zionist wagon.
Once you have people in the Labour Party viewing this tiny and very vocal group of Jewish anti-Zionists as, if not representative of the Jewish community, then certainly representing a view that can be incorporated into engagement into the Jewish community, then you have problems.
Those Jewish Labour Party members have the right to criticise the "community leaders", don't they?
Those Jewish anti-Zionists don't just tell the left that they're right and the others in the Jewish community are wrong. They tell the left that the mainstream mass of the Jewish community are not just wrong, but liars, deliberately making up allegations of antisemitism to stop socialism and to stop criticisms of Israel; and they are racist liars, because they are Zionists.
It's another form of the conspiracy theory.
As we see it, the vehicle for a lot of the antisemitism in the Labour Party today is the return of people who were formed politically in the 1980s and have been largely out of activity since then. Younger Labour supporters tend to have a different attitude on antisemitism, but most of them are not organised.
Yes. A lot of the ideas and attitudes we see today are being recycled from the 1980s. Ken Livingstone got suspended from the Labour Party in 2016, and he said nothing that he hadn't said in 1982.
We're seeing a difference between the attitudes of those older returnees and younger, idealistic members who've joined up under Jeremy Corbyn. There is something of a generational divide in attitudes.
If the Labour Party leadership asked your advice on this issue, what would you advise?
A year ago the Board of Deputies of British Jews and the Jewish Leadership Council wrote to the Labour Party with six suggestions. Eventually the Labour Party adopted the IHRA definition, under extreme duress, but essentially the party has done none of them. We're not just talking about changing processes, but changing a political culture, but there is still no recognition by the leadership of the Labour Party that they have any problem at all of an antisemitic political culture. All we hear is: it's just 0.1% of the membership, and we'll discipline them and throw them out.
How would you advise ordinary members of the Labour Party to proceed?
Educate yourself about contemporary antisemitism, about the tropes and the imagery. There's plenty of material out there.
When you're educated, bring that into your political arguments when these issues come up. Speak up. Make the arguments.
The antisemitic culture is often connected to a bullying culture in terms of how debates are directed and dominated. People in CLPs need to find a way of addressing that.
We're seeking to organise more activity in Britain in solidarity with movements like Standing Together in Israel, a joint Jewish-Arab campaign which takes up social and democratic issues within Israel and Palestinian rights. We want to show that the best solidarity with Palestinian rights goes together with combatting antisemitism. There's absolutely no reason why campaigning for Palestinian rights should go along with antisemitism. There are lots of people who campaign for Palestinian rights without being antisemitic or encouraging antisemitism.
But a lot of the antisemitism we are seeing in the Labour Party today is not flowing out of arguments over Israel-Palestine: it's quite old-fashioned antisemitism, just repackaged - conspiracy theories, stuff about the Rothschilds, stuff about Mossad controlling ISIS, way-out stuff taken from far-right websites.
And quite often the antisemitism starts with Jewish people being challenged to condemn what Israel does or is accused of doing before you can even discuss antisemitism. Jewish people may have feelings about Israel. They may not. They may have opinions about Israel. They may not. It shouldn't be obligatory for Jewish people to have a position on Israel, any more than they should be obliged to have a position on any other foreign-policy issue.
But if you want to build a programme of education around Israel-Palestine, there's an organisation called Solutions Not Sides, which brings young Israelis and Palestinians to Britain and takes them to schools and synagogues and mosques and so on.
It uses that to break down a lot of stereotypes on both sides and encourage interested audiences in Britain to humanise their own impression of people on the two "sides" when they address the conflict.