Carrying swastika banners and other neo-Nazi symbols, marchers shouted slogans such as ‘blood and soil’(the English equivalent of the Nazi phrase Blut und Boden) and “Jews will not replace us”.
Counter protestors also assembled. Dozens were hurt in the subsequent clashes, and one person was killed after a white supremacist deliberately drove a car into a crowd.
Commenting afterwards, Donald Trump said there were “very fine people, on both sides.”
Amos Schonfield, a member of the Left-wing Zionist Yachad group, was one of the bloc’s organisers at Friday’s protest.
“We wanted to make sure that we had a voice that was independent and loud,” he said.
“Five or six of us got together to say we wanted to build it, knowing that there was going to be a bigger variety [of people] than at your average kiddush, because that's what makes a Jewish Bloc a Jewish Bloc.
“We gave no recommendations to people on what they should say. The Jewish voice is a diverse and vibrant and varied one. I want to see people showing their Judaism in however it is that makes them feel Jewish.”
Posters held by Bloc participants included “Resisting Tyrants Since Pharaoh”, “Product of Refugees”, and “Oy Vey, What a Shmuck”. The most controversial was one saying “Jerusalem is not the capital of Israel”, but there were no arguments to be seen between different members of the Bloc. There was an apparent understanding that they were here for something bigger.
Imogen Resnick, another organiser, described how within 24 hours of creating the event on Facebook, “we had hundreds of people saying they were interested in coming, everyone was really excited to come out and protest against something we can all rally around.
“I guess in some ways the community has been united in its dislike of Trump. It's not polarising, because from across the spectrum people are against him.”
That dislike of Trump is not uniform across the Jewish community, however. There are people who feel that because Mr Trump is pro-Israel, Jews should support him.
Ms Resnick described this as “a very unhealthy attitude to take".
“I don't think that just because Trump is allegedly super pro-Israel - which I don't think he is anyway - you should forgive his racism and misogyny,” she said.
“Trump has emboldened white supremacists. White supremacists hate Jews. How can you dismiss that just because you think Trump is good for Israel?
“What's good for Israel isn't necessarily good for Jews in the diaspora - and people who love Israel don't necessarily love Jews. Look at the white nationalists and supremacists: many love Israel, but still despise Jews.”
As the Bloc moved slowly towards Trafalgar Square, people wearing Yarmulkes walked near those carrying a “Jewish Socialist Group” sign, while students wearing t-shirts of Zionist youth organisations made their way down the street next to a couple of older people carrying banners of the controversial pro-Jeremy Corbyn “Jewish Voice for Labour” group.
Kerry Lambeth, an American Jew living in London, said she found the sight of Jews with very different opinions marching together “reassuring".
“Especially recently, it feels like there have been some things that as a community we have strongly disagreed on, so I think it's validating to find that standing up to someone who's sort of collaborating with White Nationalists is still something that we can all agree is a bad thing.”
Charlie Kleinfeld, who identifies as non-Zionist, was carrying a sign saying Jared Kushner, Trump’s son-in-law, “is a Shanda fur de Goyim” - “a shame for us before the non-Jews”.
He said it was encouraging to see “all Jews coming together. We’ve witnessed this before, this sort of rhetoric against minorities.”
Amidst the many thousands of people at the protest, there were some antisemitic posters to be seen. One showed Trump as a puppet being manipulated by a blue Star of David. Another showed a map of America with most of the territory labelled “Israel” and asked “how would you feel”.
But, as news helicopters clattered overhead, others in the protest paused to listen to the singing coming from the Jewish Bloc.
“Oseh Shalom Bimromav, Hu Yaa’se Shalom Aleinu V’Al Col Yisrael, V’Imru Amen.”
“He who brings peace in the heights, may He bring peace on us and on all Israel, and let us say Amen.”
