The answer is section 57 of the Equality Act 2010, which says that trade organisations must not harass their members. Harassment for these purposes is defined as "unwanted conduct related to a relevant protected characteristic". Those characteristics include race and religion. To qualify as harassment, the conduct must violate the victim's dignity or create an intimidating, hostile, degrading, humiliating or offensive environment for him or her.

What Fraser was therefore trying to establish was that UCU had unlawfully harassed him by subjecting him to unwanted conduct relating to his race and religion. His strong attachment to Israel, he argued, was an aspect of his Jewish identity.

To win his case, he had to establish that the union was responsible for the conduct of those fellow members who had passed motions that were hostile to Israel. His lawyer based this claim on a concept of "institutional responsibility" that the tribunal found was "not, so far as we are aware, known to our law" and "wholly untenable". It ruled in March that the UCU did not violate Fraser's dignity or create a hostile environment. And Fraser's complaint did not meet the test of reasonableness: a political campaigner must accept the risk of being offended by his opponents' views.

Of ten complaints brought by Fraser, all but one were dismissed as without substance, devoid of merit, palpably groundless, obviously untenable or hopeless. The tenth had been brought 18 months too late.