In recent weeks Israel’s leaders have been bombarded with increasingly doom-laden scenarios about Iran’s progress towards producing a nuclear bomb, a threat that might push them towards unilateral military action if diplomacy fails.

Former generals, politicians, and academics whose expertise ranges from ballistics to theology have joined a debate that focuses on 2007 as the decisive year for halting Tehran’s perceived nuclear ambitions.

Tel Aviv University’s Institute for National Security Studies set the tone at the turn of the year with publication of its annual strategic balance, in which it warned: “Time is working in Iran’s favour and, barring military action, Iran’s possession of nuclear weapons is only a matter of time.”

Others suggest the time for diplomacy may already be over and that Israel and its allies should be preparing to strike. “Instead of allotting several months for diplomatic activity and preparing for a military strike on Iran’s nuclear infrastructure, the world continues to talk nonsense and play with illusions regarding the success of moderating diplomatic moves,” Oded Tira, the army’s former head of artillery, wrote recently.

He said President George W. Bush lacked the political power to attack Iran and suggested Israel should concentrate on lobbying his opponents in the Democratic party. “We must clandestinely co-operate with Saudi Arabia so that it also persuades the US to strike Iran,” he added.

This week, a strategic assessment from the Israeli military predicted Iran would master nuclear technology by the end of the year and would announce in March that it had crossed the nuclear threshold.

Similar concerns were voiced this week at a one-day Hebrew University seminar on the Iranian threat and more were expected to be raised during this month’s Herzliya conference, Israel’s foremost venue for debate on security issues.

A report in the UK’s Sunday Times that Israel had drawn up plans to use nuclear weapons to destroy Iran’s uranium enrichment facilities raised the temperature of the debate.

The office of Ehud Olmert, the prime minister, dismissed the claim while the foreign ministry issued a denial that reiterated the government’s previously stated policy that it sought an international diplomatic solution to the crisis.

But some analysts suggested the government might not be averse to being cast in a hawkish light. They said the perception that Israel was prepared to go ahead, if necessary unilaterally and in the near future, with military strikes against Iran might encourage pragmatists in the Tehran regime to curb the belligerency of President Mahmoud Ahmadi-nejad.

“Ahmadi-nejad’s statements are actually a gift to the Israelis because they are making the rest of the world very worried,” said Meir Javedanfar, an Iranian-born Israeli academic and co-author of a forthcoming book on the Iranian president.

Mr Ahmadi-nejad’s calls for the destruction of Israel, which might be dismissed as bombast elsewhere in the world, sound a more ominous note in Israel, which regards itself as facing an existential threat. His hosting of a Holocaust-denial conference last month was closely followed by the Israeli media.

On the diplomatic front, the Iranian president’s rhetoric, indeed, appears to have played into Israel’s hands. China and Russia supported sanctions under UN Security Council resolution 1737 in December and this week Chinese leaders told the visiting Israeli prime minister they recognised Israel’s concerns.

But some experts insist the relatively mild sanctions will not be enough to persuade Iran to suspend its alleged nuclear bomb programme.

Bernard Lewis, the influential Princeton scholar of Islam, claimed this week Mr Ahmadi-nejad and a powerful coterie around him actually wanted to provoke nuclear conflict as a means of hastening the arrival of the Mahdi, the Muslim messiah. “It would seem that he and his immediate circle really believe that the apocalyptic age is now,” he told an audience at Tel Aviv University.

Other experts put greater stress on the potential pragmatism of the Tehran leadership, pointing out that Iran’s motivation is essentially defensive and that the nuclear programme poses greater short-term threats to Sunni Arab Gulf states than it does to Israel.

“Iran sees danger from every side and therefore it seeks hegemony in the area,” said Ephraim Kam, a former Israeli intelligence colonel and a strategist at Tel Aviv University. “Iran’s concept has been one of defensive deterrence. The question is: would that doctrine change once Iran got nuclear weapons?”

The growing internal debate, including the worst-case scenario of Israel going it alone with a military strike, raises the question of whether its armed forces are capable of neutralising Iran’s threat.

Israeli aircraft destroyed Iraq’s Osirak nuclear facility in 1981, although some analysts say that only encouraged Saddam Hussein to persevere with a more clandestine nuclear programme in subsequent years.

Iran’s nuclear facilities are spread around the country and some are heavily protected below ground. Israeli forces operating on their own might face a more daunting challenge than the proponents of military action would like to admit.