Friends do not spy on friends. That illusion about America’s attitude to its allies was conclusively debunked by Edward Snowden’s revelations about America’s National Security Agency and its British partner in global electronic eavesdropping, GCHQ. But by every account, the US is being repaid in kind by one of its closest international friends – Israel.

Israel has been trying to steal secrets from the US, its principal protector and benefactor, but also occasional rival, ever since the inception of the Jewish state in 1948, and even before. But according to the latest issue of Newsweek, quoting Obama administration officials, these activities have “crossed red lines” rarely encountered in the past.

In the words of one Congressional aide, with access to classified briefings in January on the subject, Israel’s behaviour was “very sobering…?alarming…?even terrifying”. Israel, it would appear, is after everything it can lay its hands on: not just diplomatic and policy documents, but industrial and military technology. The means include Israeli trade missions to the US, joint ventures between Israeli and American companies and, presumably, spying by Israeli intelligence agencies.

“Everyone does it,” is a common reaction to such claims of ungentlemanly conduct. But by these accounts, in the case of America no one does it like Israel – not even allies with intelligence services as skilled as those of France, Germany, even the UK.

The latest charges surfaced as Susan Rice, Mr Obama’s national security adviser, was on a visit to Jerusalem to discuss the Middle East peace process, Iran and other regional issues. They have drawn predictable, outraged denials from Israeli spokesmen. “A malicious fabrication aimed at harming relations,” declared Avigdor Lieberman, the Foreign Minister, adding that “we do not engage in espionage in the US, neither directly nor indirectly”. Off the record, other officials mutter darkly about anti-Semitism.

The controversy illustrates the complexity of the relationship between two allies who share a common enemy in radical Islam, pool vast quantities of intelligence and never miss an opportunity to profess their unshakeable commitment to each other – yet whose mutual interests and mutual trust have unspoken but very definite limits.

Israel’s appetite for intelligence is driven by the survival instinct of a nation surrounded by enemies, and whose suspicions can be quickly aroused by any US dealings with its neighbours to which it is not party. The US, for its part, spies on Israel for similar reasons, to gain prior knowledge of any unilateral action it might plan (an attack on Iran, for instance) that could jeopardise US interests.

The new claims coincide with stalled efforts by Israel to secure admission to the US visa waiver programme, from which 38 countries currently benefit. Hitherto, the assumption was that two issues were causing the hold-up on Capitol Hill: accusations of discrimination against Arab- and Muslim-Americans seeking entry to Israel, and a growing number of young Israelis who overstay tourist visas and work illegally in the US. Now, however, a third problem looms at least as large – the worry of US national security agencies that any loosening would make it easier for Israeli spies to enter the country.

On the face of it, the delay is still surprising, given the legendary influence that the Israel lobby wields among US lawmakers (influence that once prompted the right-wing gadfly and former presidential candidate Pat Buchanan to describe Capitol Hill as “Israeli-occupied territory”).

But if spying is involved, such influence would seem to have its limits. “They thought they could just snap their fingers,” a Congressional staffer told Newsweek, and Israel’s friends would get the business done, bypassing the immigration authorities and the Department of Homeland Security. But not so.

Nor has it been so in the case of Jonathan Pollard, the most notorious Israeli spy in the US. Mr Pollard, a Jewish-American naval intelligence analyst, was sentenced to life in prison in 1987 for passing US secrets to Israel. For years, his supporters, prominent Americans as well as a formidable lobby in Israel led by the current Prime Minister, Benjamin Netanyahu, have sought to secure his freedom.

But all such efforts have failed, most recently when John Kerry, the Secretary of State, dangled Mr Pollard’s release as a carrot to persuade Mr Netanyahu to extend peace talks with the Palestinians. But opposition to the idea was remarkably widespread, not just in the US intelligence community, but in the media – even though Mr Pollard, who has already spent 27 years behind bars, is due for parole in 18 months.

But the Pollard affair is a single chapter in a very long history. Long before his treachery, US authorities were uncovering cases of Israeli espionage. Zionist agents worked in America even before Israel existed, seeking money and material for the cause. Decades ago, John Davitt, head of internal security at the Justice Department between 1950 and 1980, declared that throughout his tenure the Israeli intelligence service was the second most active in the US after the Soviet Union’s.

In 2001 dozens of Israelis were arrested or held on suspicion of being part of a giant spy ring, and a US government report after 9/11 concluded that Israel ran the most aggressive espionage operation against the US of any ally. Three years later, two officials of Aipac, America’s most powerful pro-Israel lobby group, were charged with spying, for passing to Israel official documents on US policy towards Iran. The case was dropped in 2009 – but how many others have been, or will be, quietly brushed under the carpet can only be guessed at