He invited to Parliament a Palestinian Islamist, Raed Salah, who has suggested Jews were absent from the World Trade Center on 9/11. Corbyn called him an honored citizen.
https://www.nytimes.com/2016/03/08/opinion/an-anti-semitism-of-the-left.html?_r=0
He " once described it as his honour and pleasure to host our friends from Hamas and Hezbollah in parliament"
https://www.theguardian.com/commentisfree/2015/aug/13/jeremy-corbyn-labour-leadership-foreign-policy-antisemitism
Yet negotiation is not on Hamass agenda, as Corbyn ought to know. In its charter Hamas states: Initiatives, and so-called peaceful solutions and international conferences, are in contradiction to the principles of the Islamic Resistance Movement
There is no solution for the Palestinian question except through jihad.
It isnt a peaceful negotiated solution that Hamas wants; its the destruction of the Jews. Here is a direct quote from Hamass charter: The prophet, prayer and peace be upon him, said: The time will not come until Muslims will fight the Jews (and kill them); until the Jews hide behind rocks and trees, which will cry: O Muslim! there is a Jew hiding behind me, come on and kill him!
https://www.theguardian.com/commentisfree/2015/aug/13/jeremy-corbyn-labour-leadership-foreign-policy-antisemitism
Written a letter defending Stephen Sizer, the vicar disciplined by the Church of England for linking to an article on social media entitled 9/11: Israel Did It;
https://www.theguardian.com/commentisfree/2015/aug/13/jeremy-corbyn-labour-leadership-foreign-policy-antisemitism