The level of anti-Israel activity on British campuses is "overwhelming" and not enough is being done to combat it, according to a former academic in Islamic studies.
Denis MacEoin, former editor of the Middle East Quarterly, led criticism of one student association which attempted to implement a boycott of Israel earlier this year.
His letter to the Edinburgh University Students' Association, attacking their plans, has now been forwarded around the world by Israel supporters.
Dr MacEoin, who is not Jewish, now believes the situation at universities has deteriorated to the extent that "things will not get better".
He said: "I've completely given up on getting pro-Palestinian students and others to listen to a single thing. They have gone beyond a certain point and they are beyond all reason.
"You can only reason with people who are not at that level. The extreme left behave in such an insane way.
"The case at St Andrews with Donnachie was worrying because it was so deeply offensive how he behaved. It was good that he was expelled from the university.
"It makes no sense at all, emotionally, for gay [pro-Palestinian] people in this country to attack the one country that gives rights to, and takes in, gay refugees. What's going on in their brain? That's what upsets me."
Dr MacEoin's letter to Edinburgh students in April attacked those who compare Israel to Nazi Germany, picked apart their claim that Israel was an apartheid state, and highlighted the rights Arabs and homosexuals have in Israel. He wrote: "University is supposed to be about learning to use your brain, to think rationally, to examine evidence, to reach conclusions based on solid evidence, to compare sources, to weigh up one view against one or more others.
"If the best Edinburgh can now produce are students who have no idea how to do any of these things, then the future is bleak."
Reflecting on the letter's acclaim, he said: "Something struck a chord for some reason. I've had a couple of responses from the association's president recently. All I was complaining about was the actual vote for the boycott and the overwhelming majority that voted for it. It doesn't matter that it didn't become policy."
The Newcastle-based academic has had responses to his letter from around the world, including one from a Palestinian living in Ramallah.
It was not the first letter Dr MacEoin has sent in support of Israel. In the past year he has also written to Green Party leader Caroline Lucas, Defence Secretary Liam Fox, and the head of the Quakers's Middle East programme.
He also wrote to Tamar Fogel, the daughter and sister of the victims of the Itamar terror attack in March.
Read Dr MacEoin's letter here