Ever since the 1965 inauguration of the Dimona plant in the southern Negev desert, the one-time workplace of the whistleblower Vanunu, Israel has consistently refused to deny or confirm that it possesses nuclear arms.
But even before Vanunu, who is to be released on Wednesday after 18 years in prison, leaked details of the program to Britain's Sunday Times newspaper in 1986, the official policy of ambiguity had left few people fooled.
Israel currently has two nuclear facilities, the reactor at Dimona in the Negev desert built with French aid and capable of producing weapons-grade plutonium and a smaller research reactor at Nahal Sorek, south of Tel Aviv.
Under an understanding with the United States dating back to 1969, Israel has committed itself to abstain from any comment on its nuclear potential and not to carry out nuclear tests.
In return, the United States does not pressure Israel to adhere to the nuclear Non-Proliferation Treaty (NPT), which would oblige the Jewish state to submit its nuclear facilities to international supervision by the UN's atomic watchdog, the International Atomic Energy Agency.
The agency's Director General Mohamed ElBaradei recently urged Israel to give up its nuclear arsenal, claiming it spurred a regional arms race.
"I am not happy with the status quo, because I see a lot of frustration in the Middle East due to Israel's sitting on nuclear weapons or nuclear weapons capability, while others in the Middle East are committed to the NPT," he told the Israeli daily Haaretz.
As an extra precaution, the whole program is also covered by military censorship, which the Israeli media regularly bypasses by quoting foreign publications.
According to these "foreign experts", Israel has used its reactor at Dimona to produce around 200 nuclear warheads.
Peter Hounam, the journalist who first broke the Vanunu story for the Sunday Times, criticised Israel's "gall" for still failing to come clean about its capabilities but said it was determined not to upset its allies in Washington.
But its decision to try to gag Vanunu at all costs even after his release was likely to backfire and serve to increase demands for clarity, he added.
"I think that the international reaction to the way he is being treated will add to the impetus for the UN" being given access to the Dimona plant, he told AFP.
"Everything about this stinks of hypocrisy," he added.
No Israeli leader has ever broken the long-standing taboo by unequivocally recognising the existence of a nuclear arsenal, but allusions have become less and less oblique.
The former premier Shimon Peres, considered the father of Israel's nuclear program after reaching agreement with France back in 1956 for the provision of a nuclear reactor and uranium, effectively confirmed its existence in an interview with French television in 2001.
"The suspicion and the fog which surround this project are constructive, for it increases our power of deterrence," said Peres in a documentary on Dimona.
Peres, who was director at Israel's defence ministry in the 1950s, has no sympathy for Vanunu's decision to turn the spotlight on the nuclear issue.
"He betrayed his country and that's it," Peres told reporters recently.
"Nobody gave him permission or authority to do things against his own country."