A mental health trust and a trade union discriminated against a conflict resolution expert because he was Israeli, a court has been told.

Moty Cristal was due to run a workshop for staff at the Manchester Mental Health and Social Care Trust in May last year, but the event was cancelled when members of Unison objected to his nationality, it is alleged.

Professor Cristal, who is from Tel Aviv, is seeking damages totalling £26,500 for loss of earnings — he was due to be paid £3,500 for the session — injury to his feelings, and aggravated damages.

At the opening of a hearing into the case on Wednesday, Dinah Rose QC said Prof Cristal had been informed the workshop was cancelled “because Unison had objected to him delivering the training and had made it clear to the Trust that if he were to attend, its members would boycott the workshop”.

Ms Rose told Central London County Court that her client had a “genuine and serious grievance”. The Trust and union had “conspired” to discriminate against him, she told the court.

“This is not simply a claim about money. What Prof Cristal is seeking is the vindication of his right to equal treatment without discrimination, particularly on racial grounds.”

The case was due to continue until Friday, with Judge David Mitchell then expected to reserve his judgment.