Sorry if this has already been covered but I only just heard this story and am horrified.
My understanding is that at an antisemetism event Jeremy Corbyn made an antisemetic comment. Ruth Smeeth, a Jewish Labour MP challenged him on it and was shouted down by someone thought to have links with the Momentum group, accused of colluding with the media and had to leave the room in floods of tears.
www.independent.co.uk/news/uk/politics/labour-antisemitism-jeremy-corbyn-ruth-smeeth-jewish-mp-accused-of-colluding-with-media-a7111061.html