A Jewish holocaust survivor honoured by the Queen has hit out at Jeremy Corbyn over his handling of alleged anti-Semitism in the Labour Party.
Retired doctor and immunologist Martin Stern accused the Labour leader of building a reputation as a humanitarian "on false premises" and revealed he had "serious concerns" about recent stories of anti-Semitism.
Dr Stern, who collected an MBE at Buckingham Palace on Friday morning, arrived in the UK aged 12 in 1950 after his parents were both killed during the Second World War.
The 79-year-old was honoured for his services to holocaust education and compared Mr Corbyn to literary character Don Quixote, for whom Israel represents an "evil giant".
It comes after Mr Corbyn faced angry recriminations on Friday over his alleged failure to tackle anti-Semitism in the Labour Party after it lost out to the Tories in Barnet, one of the most strongly Jewish boroughs in the country, in the local elections.
Dr Stern told the Press Association: "It concerns me very seriously and it is not only Jews who are affected ... we need politicians not only of high intellectual calibre but with intellectual courage.
"In politics a lot of trouble comes from people who have got a theory according to which they can run the human race.
"They make the facts conform to their theory ... a human being needs to be open to new facts.
"I think currently we have a problem with the quality of top politicians, and in the case of one of them he is a kind of a Don Quixote for whom Israel is the windmill that he imagines to be an evil giant."
He added: "There are people who make themselves feel good by portraying others as bad ... no human being is perfect, no state is perfect, but this kind of biased, political attitude, designed to steal the good reputation as it were.
"To get a reputation as a humanitarian but on false premises is to be condemned."
Asked what he would say to Mr Corbyn if they were to sit down together, Dr Stern said: "The problem with being an ideologue is you're not open to discussion.
"There are people far better than me doing that ... it seems to me that my task is to talk to people whose minds have not been frozen into rigidity yet and to teach them and question and think and not necessarily hold my view but to keep searching for facts, keep looking at the possibility that I might be wrong or they themselves may be wrong.
"As human beings we are not infallible and humility and self-questioning needs to be part of any healthy human being and even more so of any politician."
Dr Stern travels across the UK to speak at schools, universities and events to teach about the dangers of intolerance and speak of his own experiences.
He volunteers with both the National Holocaust Centre and Museum and the Holocaust Educational Trust and is also central to the Forever Project which aims to keep alive stories of survivors.
Dr Stern also works closely with academics at Leicester University, speaking at academic conferences about the psychology behind genocide.