A battle over the legal costs relating to a defeated claim of antisemitic harassment is set to continue after a tribunal withdrew from deciding the issue.

The University College Union is trying to recover costs — understood to be around £600,000 — following the action brought against it by the director of the Academic Friends of Israel, Ronnie Fraser, who said its policy on Israel amounted to harassment.

The same tribunal, headed by Judge Anthony Snelson, which had rejected Mr Fraser’s claim in April was due to hear the case for costs.

But lawyers for Mr Fraser and for the solicitors who represented him in the harassment case, Mishcon de Reya, argued that the tribunal had been so scathing in their original ruling that they could not fairly settle the question.

The tribunal had dismissed Mr Fraser’s claim as “a sorry saga” and “an impermissible attempt to achieve a political end by litigious means”.

The UCU will now have to go to a new tribunal. Judge Snelson said: “We must recuse ourselves and a cost application should be listed before another tribunal.”