The BBC has been criticised after the writer Gordon Thomas claimed on Radio 4 that up to a million Jews around the world are on hold to assist Mossad.

Mr Thomas, author of Gideon's Spies, a widely-challenged book about the Mossad, was interviewed by presenter Eddie Mair on BBC Radio 4's PM programme last week about the Dubai assassination of Hamas leader Mahmoud al-Mabhouh last month.

Media reports have claimed that the Israeli intelligence service was behind the hit.

During the interview, Mr Thomas, who has been on radio and TV as an apparent authority on the Mossad, said: "They [the Mossad] have a whole back-up system... These are people who are local residents, Jewish people who will help the Mossad and there are estimated to be in the world about half a million, some people say a million, I tend to say half a million from what I've learnt from the Mossad people."

The BBC has received three complaints following the programme.

A Board of Deputies spokesman said that the comment was "absurd".

Douglas Murray, director of the Centre for Social Cohesion, said on his blog: "The idea that up to a million of them [Jews] keep this secret knowledge strikes me as not just one of the most ridiculous, but in the present climate one of the most dangerous, ideas for the BBC to pump into circulation."

A BBC spokesman said: "This interview was part of a wider piece about the assassination of Mahmoud al-Mabhouh which involved contributions from a number of people including Gordon Thomas.

"The sentiments expressed by Gordon Thomas were clearly his own opinions. They came at the end of the interview... and there was no time to come back on them."

A Board of Deputies spokesman said: "The comments would be more appropriate in the realm of fictional stories about spies than in the real world."

And the book…

"They [the Mossad] have a whole back-up system... These are people who are local residents, Jewish people who will help the Mossad"