The author of a new book sympathetic to Israel believes his views ultimately cost him his job at the UK’s most prestigious foreign-affairs think tank.

Robin Shepherd, whose new book, A State Beyond the Pale — Europe’s Problem with Israel explores hostility towards the Jewish state, says his pro-Israel position put him at odds with the leadership of London’s Chatham House.

At a book launch at a London synagogue last week, Mr Shepherd recalled an op-ed piece he had written for The Times in January 2008 defending Israel’s actions against terrorism, which had resulted in an “aggressive” email from Chatham House director Robin Niblett.

“It didn’t result in my leaving immediately,” he said, “but it broke the relationship I had with my boss at the time.”

In the article, Mr Shepherd blamed Hamas for the situation in Gaza and hit out at the “frenzied onslaught” against Israel among commentators in Europe.

He contended that the rockets fired by Palestinians since Israel’s withdrawal from Gaza defeated the argument, put by “apologists for extremism”, that occupation, rather than ideology, was the root cause of terrorism.

But Dr Niblett wrote that the article was “polemical in tone and content” and that he was concerned at the “potential damage you have done to the institute’s reputation for thoughtful and balanced insight”.

He wrote: “I do not have confidence in your knowledge of the situation in Gaza or of what motivates terrorists there to lob rockets on Israeli civilians. I do have confidence in your knowledge of European politics.... I hired you for the latter, not the former.”

But Mr Shepherd, who joined another think tank, the Henry Jackson Society, in March this year, said his Chatham House contract had included the writing of a book on European attitudes to Israel.

“What particularly shocked me about the whole affair is that at an institute with a mission statement of ‘independent thinking on international affairs’, I was subjected to such fierce intimidation for honestly-held views about European attitudes to Israel,” Mr Shepherd said.

Another former employee of the institute recalled that “all hell broke loose” at the time of the article and claimed that the institute basically adopted a “pro-Palestinian” line.

But Dr Niblett said this week that the institute’s work on Israel was “fair and objective” and that the record of its Middle East programme over the last two or three years “speaks for itself. We have good relationships with a number of Israeli organisations including Bicom. We do events with them, we do events on Israel and we have two Israeli associate fellows at Chatham House.”

He declined to comment on Mr Shepherd’s claims.

Asked whether the Israeli Embassy had suspended its membership of Chatham House, Dr Niblett said: “It’s fair to say that a conversation is going on, but their membership has not lapsed from our perspective, and there is nothing in writing saying that it has.”

He said he was due to see the Israeli ambassador shortly. “I’m pretty confident we are going to be on the same sheet at the end of the process,” he said.

A spokesman for the Embassy would say only that it was in “candid correspondence” with Chatham House.