There's a slightly confusing article on the Guardian website today about a raucous anti-Semitism debate at the annual conference of Britain's National Union of Students.

Feelings ran so high in the debate at Blackpool that the chairman was forced to ban the taking of photographs and filming on the conference floor as some unidentified delegates were heard to shout "we have your photographs on file" at speakers.

Quite who the people shouting were, and who they were shouting at, is not explicitly clear, but the topic of discussion "whether the NUS should implement the European Monitoring Centre on Racism and Xenophobia's (EUMC) working definition of anti-Semitism" clearly brought out the worst in some people.

The contentious issue was the EUMC's inclusion that "such manifestations could also target the state of Israel, conceived as a Jewish collectivity".

In other words: criticism of Israel can sometimes be anti-Semitic. True or False?

When some delegates suggested a secret ballot, NEC member Sam Lebens struggled to contain his anger as he stood up to oppose it.

"The Jewish community has put forward a motion for you to consider, if you want to tear it up have the decency to show you are doing it," he said.

When Mr Lebens asked if he looked "like someone who doesn't care about Palestinian children" he was booed. Undeterred, he continued: "Don't hide behind secret ballots. No criticism of Israel is illegitimate. Anti-semitism is."

The motion to adopt the EUMC definition was passed, The vote comes just a day before the BBC reported a rise in anti-Semitic incidents in the UK, noting that university campuses are one area of society where such views are prevalent.