"The true reason of course, is that the FO [Foreign Office] has a ban on official royal visits to Israel, which is even more powerful for its being unwritten and unacknowledged," he said. "As an act of delegitimization of Israel, this effective boycott is quite as serious as other similar acts, such as the academic boycott, and is the direct fault of the FO Arabists."
One of Britain's most eminent historians has assailed the country's policy towards Israel, questioning why Queen Elizabeth IIhas visited a host of despotic regimes but has never made an official visit to the Holy Land.
Speaking at the Anglo-Israel Association dinner in central London last week, Andrew Roberts suggested that the Foreign Office had a de facto ban on royal visits to Israel.
Roberts's book A History of the English-Speaking Peoples Since 1900 brought him an invitation to the White House in February 2007, where he delivered the prestigious White House Lecture.
Roberts, whose work includes biographies of Churchill and Chamberlain, as well as Hitler and Roosevelt and a look at the relationship between Napoleon and Wellington, said that Britain had been at best "a fair-weather friend" to Israel.
The 400 attendees at the dinner, held at the prestigious Grosvenor House Hotel on Park Lane, included ambassadors, diplomats, lords and Christian leaders celebrating the 60th anniversary of the AIA, the oldest organization of Anglo-Israel friendship in the UK.
Roberts told them that he wanted to try to strip away some of the myths surrounding the relationship between Israel and Britain.
"It is, therefore, no coincidence that although the Queen has made over 250 official overseas visits to 129 different countries during her reign, neither she nor one single member of the British royal family has ever been to Israel on an official visit," he said.
Even though, he said, Prince Philip's mother, Princess Alice of Greece, was recognized as a Righteous Among the Nations for sheltering a Jewish family in her Athens home during the Holocaust, and is buried on the Mount of Olives, Prince Philip did not visit her grave until 1994 - "and then only on a private visit."
Roberts questioned the Foreign Office's attitude to Israel, because it is the Foreign Office that organizes and sanctions royal visits.
The Foreign Office has responded that Israel was not unique in not having received an official royal visit, as "many countries have not had an official visit," Roberts said.
"That might be true for Burkino Faso and Chad, but the FO has somehow managed to find the time over the years to send the queen on state visits to Libya, Iran, Sudan, Kuwait, Bahrain, Qatar, the United Arab Emirates, Oman, Saudi Arabia, Tunisia, Algeria, Morocco, Jordan and Turkey. So it can't have been that she wasn't in the area.
"Perhaps her majesty hasn't been on the throne long enough, at 57 years, for the Foreign Office to get round to allowing her to visit one of the only democracies in the Middle East.
"At least she could be certain of a warm welcome in Israel, unlike in Morocco, where she was kept waiting by the king for three hours in 90-degree heat, or at the Commonwealth heads of government meeting in Uganda the time before last, where they hadn't even finished building her hotel."
Roberts, whose current book The Storm of War: A New History of the Second World War reached No. 2 on the Sunday Times best-seller list, also attacked those who accuse Israel of responding "disproportionately" to provocation.
"William Hague [a Conservative MP] called for Israel to adopt a proportionate response in its struggle with Hizbullah in Lebanon in 2006, as though proportionate responses ever won any victories against fascists," he said.
"In the Second World War, the Luftwaffe killed 50,000 Britons in the Blitz, and the Allied response was to kill 600,000 Germans - 12 times the number and hardly a proportionate response, but one that contributed mightily to victory. Who are we therefore to lecture the Israelis on how proportionate their responses should be?"
He then questioned how Britain would respond to similar provocations faced by Israel.
"Very often in Britain, especially when faced with the overwhelmingly anti-Israeli bias that is endemic in our liberal media and the BBC, we fail to ask ourselves what we would do placed in the same position?
"The population of the UK is 63 million - nine times that of Israel. In July 2006, to take one example entirely at random, Hizbullah crossed the border of Lebanon into Israel and killed eight patrolmen and kidnapped two others, and that summer fired 4,000 Katyusha rockets into Israel which killed a further 43 civilians.
"Now, if we multiply those numbers by nine to get the British equivalent, just imagine what we would not do if a terrorist organization based as close as Calais were to fire 36,000 rockets into Sussex and Kent, killing 387 British civilians, after killing 72 British servicemen in an ambush and capturing a further 18?
"I put it to you that there is absolutely no lengths to which our government would not go to protect British subjects under those circumstances, and quite right, too. So why should Israel be expected to behave any differently?"
US President Barack Obama was also criticized by Roberts.
"At a time when Barack Obama appears to be the least pro-Israeli president since [Dwight] Eisenhower, the dangers are even more obvious. For there is simply no way that Obama will prevent [Iranian President Mahmoud] Ahmadinejad, perhaps Jewry's most viciously outspoken and dangerous foe since the death of Hitler, to acquire a nuclear bomb," he said.
Ending his speech to rapturous applause, Roberts said Israel, and Israel alone, knew how to act in the best interest of the Jewish people.
"In her hopes of averting the threat of a second Holocaust, only Israel can be relied upon to act decisively in the best interests of the Jews," he said.
His books have been translated into Dutch, Finnish, French, German, Hebrew, Hungarian, Japanese, Chinese, Korean, Norwegian, Polish, Portuguese, Russian, Estonian and Spanish.