Jeremy Corbyn described unspecified Israeli politicians as “criminal” and criticised the fairness of BBC coverage of Palestine, in a letter to William Hague written two years before he became Labour leader.

The letter is one of a series written by Mr Corbyn to Foreign Office ministers, released following a Freedom of Information request.

The Labour leader has been a longstanding and outspoken critic of Israel’s illegal settlements in Palestinian territory and its blockade of Gaza.

In a letter to Mr Hague, the then Foreign Secretary, in March 2013, he describes a recent visit to Gaza, which he said resembled “one huge suffering refugee camp”.

“At one of the meetings I attended I was asked if we would, at the very least, a) stop allowing Israel’s criminal politicians to come to our country freely, b) if we would ensure the BBC portray Palestine fairly and c) if we would end the siege of Gaza,” he writes.

“Had I not been working toward all of these three aims I’d have hung my head in shame,” he adds. “There was no possible explanation I could give as to why our governments had made no progress in support of such crucial aims.”

It is not clear which Israeli politicians Mr Corbyn was referring to. The former Israeli Prime Minister, Ehud Olmert had been convicted of a charge of ‘breach of trust’ by the time the letter was written and has since been jailed on a later charge of bribery.

Former Israeli Prime Minister Ehud Olmert (Reuters)

In the letter, Mr Corbyn goes on to criticise the BBC for having “barely mentioned” that Palestinian prisoners were undertaking a hunger strike in protest against Israel’s actions.

Since becoming Labour leader, Mr Corbyn has had a fractious relationship with the BBC, and described the corporation as “obsessed with trying to damage the leadership of the Labour party” in a recent documentary for Vice.

In another letter to Mr Hague, written in February 2012, Mr Corbyn calls on the UK Government to impose trade sanctions on Israel over the eviction of Palestinians from East Jerusalem.