Efforts to have Israeli diplomats banned from a university campus have been condemned by the Israeli Embassy.

Dozens of students, academics, alumni, University College Union members and two trade unions signed a petition condemning Liverpool University's invitation to Alon Roth-Snir, Israel's deputy ambassador to the UK. He is due to speak to politics students at the university on Wednesday.

Led by Liverpool's Guild of Students president, Maev McDaid, the boycott call implored the politics department to rescind its invitation and "deny any platform on our campus that might facilitate attempts to justify breaches of international law and human rights".

The petition quotes Archbishop Desmond Tutu's comparison of Israel to the former apartheid regime in South Africa, and references blood libel Islamic cleric Raed Salah.

An Israeli Embassy spokesman said: "Universities are the place for freedom of speech. If a long list of students don't know the first thing about the academic world, then the university is in real trouble."

Meanwhile, National Union of Students president Liam Burns condemned "vile" antisemitism after activists vandalised a Union of Jewish Students' stall at NUS conference.

Jewish students discovered stickers calling for people to "boycott Israeli goods" plastered across the UJS sign and star of David symbol.

The attack happened on Tuesday evening after UJS members had left the stall in Sheffield.

A UJS spokesman said: "There is no excuse for this behaviour within the student movement. The singling out of Jewish students and the direct attack on Jewish religious symbols is antisemitism."

Mr Burns, who was re-elected as president for a second term, told delegates that NUS did not tolerate racism, fascism or antisemitism in any form. "Antisemitism is vile. It is hate and has no place in our movement. We will work day and night to drive hate out of our student movement, education system and society."

NUS launched an investigation, while members gathered signatures urging colleagues to "stand in solidarity with Jewish students victimised at this year's conference". Chief Rabbi Lord Sacks had addressed students at a fringe session earlier on Tuesday evening - his first appearance at NUS conference.

He told them: "University is the school for justice and justice means giving a fair hearing to all. That is the precondition of justice. No group should feel intimidated at university."

On the conference floor, a report presented by NUS's national executive council and "liberations" section included a series of policies attacking Israel and demanding "freedom for Palestine".

A section on "international peace and justice" called for NUS to work more closely with the Palestine Solidarity Campaign and Stop the War Coalition.

There was also sympathy for the plight of Israeli women discriminated against by "some ultra-Orthodox Jewish men" and those living in Sderot under the threat of rocket attacks from Gaza.

NUS national leaders are under no obligation to adopt the policies.