Prince Charles was fiercely criticised last night after it emerged he once urged the US to ‘take on the Jewish lobby’ – and blamed ‘the influx of foreign Jews’ for causing unrest in the Middle East.

The Mail on Sunday can reveal the incendiary comments are contained in a letter in which the Prince lays bare his thoughts on one of the world’s most bloody disputes.

Writing to his close friend Laurens van der Post in 1986, the Prince makes a startling assessment of the Arab-Israeli conflict.

He argues it was the exodus of European Jews in the middle of the last century that ‘helped to cause the great problems’.

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Desert Storm: Charles and Diana visit Saudi Arabia in 1986, pictured, the year he wrote his controversial letter

He goes on to say terrorism in the region will only end when its causes are eliminated.

He then expresses the hope a US President will find the courage to stand up to the American ‘Jewish lobby’.

The term ‘Jewish lobby’ is considered by many to be anti-Semitic – suggesting wealthy Jews in the US operate behind the scenes to exercise undue influence over government policy.

Other high-profile figures have been heavily criticised for using the term.

Dodgy views: Charles, pictured with President Ronald Reagan in 1985, was said to be critical of US Middle East policy

Last night, Stephen Pollard, influential editor of The Jewish Chronicle, said: ‘To me this is the most astonishing element of the Prince’s letter. The “Jewish lobby” is one of the anti-Semitic themes that have endured for centuries. It is this myth there are these very powerful Jews who control foreign policy or the media or banks or whatever.’

Mr Pollard described the letter as ‘jaw-droppingly shocking’, adding: ‘That they [the Prince’s comments] come from the heir to the throne is unsettling, to put it mildly.’

While the letter is inflammatory, there is no suggestion Charles holds anti-Semitic views.

He has many prominent Jewish friends and in 2013 became the first Royal to attend a chief rabbi’s inauguration ceremony. In a speech that year, he expressed concern at the apparent rise of anti-Semitism in Britain.

In the past it has been reported that the Prince is privately critical of US policy in the Middle East, with one diplomatic source accusing him of having ‘fairly dodgy views on Israel’.

Charles has always enjoyed a close and supportive relationship with the Jewish community in Britain.

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At the same time, he is seen as a defender of Islam, with one historian noting that no other major Western figure has as high a standing in the Muslim world.

It has also been suggested he has pro-Palestinian leanings, a perception the letter appears to support.

State that offered hope for survivors of the Holocaust Jews from Eastern Europe had been arriving in Palestine - part of which would later become Israel - even before 1917, when the Balfour Dedclartion set in motion the creation of the Jewish state. Among those who came after the end of the Second World War in 1945 were many survivors of the Holocaust. In May 1948, when Israel came into existence, five Arab nations - Egypt, Jordan, Iraq, Syria, and Lebanon - invaded but were defated by the Israeli military. From 1948 to 1951, nearly 700,000 immigrants - many of them from refugee camps in Germany, Austria and Italy - arrived to settle in Israel. Advertisement

The Prince’s candid letter surfaced in a public archive.

It was written on November 24, 1986, immediately after an official visit the then 38-year-old Prince made to Saudi Arabia, Bahrain and Qatar with Princess Diana.

He notes the tour was ‘fascinating’ and that he learned ‘a lot about the Middle East and Arab outlook’.

He goes on: ‘Tried to read bit of Koran on way out and it gave me some insight into way they [Arabs] think and operate. Don’t think they could understand us through reading Bible though!

'Also I now begin to understand better their [Arabs’] point of view about Israel. Never realised they see it as a US colony.

'I now appreciate that Arabs and Jews were all a Semitic people originally and it is the influx of foreign, European Jews (especially from Poland, they say) which has helped to cause great problems. I know there are so many complex issues, but how can there ever be an end to terrorism unless the causes are eliminated?

‘Surely some US president has to have the courage to stand up and take on the Jewish lobby in US? I must be naive, I suppose!’

Incendiary letter to his mentor, explorer Laurens van der Post: Prince Charle's candid views on the Middle East were made to close friend Laurens van der Post, the late Afrikaner author, war hero and explorer who was godfather to Prince William...

Among those to come under fire for using the term ‘Jewish lobby’ are General George Brown, the highest-ranking military officer in the US as chairman of the Joint Chiefs of Staff, who was publicly rebuked and disowned by President Gerald Ford in 1974 after claiming that a ‘Jewish lobby’ controlled Congress.

Former Ukip leader Nigel Farage was criticised earlier this month when he referred to ‘a powerful Jewish lobby’ in the US.

In 2006, Chris Davies, former leader of the Lib Dem MEPs, was forced to resign after he used the term.

Archbishop Desmond Tutu also came under fire when he used the phrase in a newspaper article in 2002.

The Prince’s reference in the letter to the influx of European Jews also caused dismay.

It is not clear if he is referring to immigration before or after the Second World War, or both. Mr Pollard said: ‘It is the absolute classic Arab explanation of the problems in the Middle East.

'And it is what everyone has always said the British aristocracy actually thinks – the idea that Jews were some kind of foreigners who had no real place in Israel until we decided to make it their homeland. Historically it is nonsense and it’s quite stunning when it comes from the heir to the throne.’

A senior Israeli diplomatic source said last night: ‘He [Charles] was travelling around the Gulf states [just before he wrote the controversial letter], which in those years were very anti-Israel. It seems he was presented with a narrative in a very convincing way.’

Earlier this month, Britain marked the centenary of the Balfour Declaration, the document that paved the way for the state of Israel, with a gala dinner in London attended by Theresa May and Israeli prime minister Benjamin Netanyahu.

The Prince called the centenary a ‘deeply significant moment’, adding ‘a great deal remains to be done if we are to bring about a just and lasting peace for Israel and her neighbours’.

Suggestions that Charles holds pro-Palestinian views are supported by his letter to van der Post.

He writes there is much to admire about Islam ‘especially its accent on hospitality and accessibility of rulers’.

In 1993, Charles delivered what was then considered to be the most pro-Islamic speech ever made by a member of the Royal Family.

He said: ‘Islam can teach us today a way of understanding and living in the world which Christianity is poorer for having lost.’

He added: ‘These two worlds, the Islamic and the Western, are at something of a crossroads in their relations. We must not let them stand apart.’

In 2003, it was reported the Prince had not been to the US for the previous six years on Foreign Office advice, largely because of his criticism of US policy in the Middle East.

A diplomatic source said at the time the Prince had ‘in American terms and international terms, fairly dodgy views on Israel. He thinks American policy in the Middle East is complete madness.’

In 2007, leaked emails between senior Clarence House staff put Charles at the centre of a row about the Royals’ attitude towards the Jewish state.

Exchanges between Sir Michael Peat, the Prince’s then principal secretary, and Clive Alderton, Sir Michael’s deputy, contained apparently disparaging remarks about Israel.

Earlier that year, the Israeli embassy invited the two senior aides to Israel for a four-day visit as guests of the Knesset, the Israeli parliament.

Sir Michael initially replied enthusiastically, saying: ‘The invitation is hugely appreciated and Clive and I would love to come.’

But a month later, there was an exchange of emails between Mr Alderton and Sir Michael that were apparently accidentally copied to the outgoing Jewish ambassador.

In the emails, Mr Alderton complains of being ‘pursued’ by the ambassador and says: ‘Safe to assume there is no chance of this visit ever actually happening?

'Acceptance would make it hard to avoid the many ways in which Israel would want HRH [Prince Charles] to help burnish its international image. In which case, let’s agree a way to lower his expectations.’

Over the years, the Prince has forged a close relationship with the Saudi royal family. But no Royal has ever visited Israel in an official capacity.

Officials say it is because there is no permanent peace deal in the region.

Earlier this year, however, Charles was pencilled in to visit the country to mark the Balfour centenary and honour thousands of British war dead.

But the idea was vetoed by the Foreign Office amid claims it would upset Israel’s Arab neighbours.

Last night a Clarence House spokeswoman said of the 1986 letter: ‘This letter clearly stated that these were not the Prince’s own views about Arab-Israeli issues but represented the opinions of some of those he met during his visit which he was keen to interrogate.

'He was sharing the arguments in private correspondence with a long-standing friend in an attempt to improve his understanding of what he has always recognised is a deeply complex issue to which he was coming early on in his own analysis in 1986.

'Over the years, the Prince has continued his study of the complex and difficult themes he referenced here. He has built a proven track record of support for both Jewish and Arab communities around the world and has a long history of promoting interfaith dialogue and cultural understanding.’