Meir Dagan could never be described as a lily-liveredliberal.

In eight years at the head of Mossad, he embarked on a series of clandestine operations that, according to senior Israeli officials, "stopped at nothing to disrupt the axis between Iran, Syria, Hamas and Hizbollah". This includes a series of assassinations that Israel will never take responsibility for, but leave little doubt in the Middle East as to their authorship.

So when last month, after eight years of silence, a newly retired Dagan took twice to public podiums to lambast the idea of a military strike against the Iranian nuclear installations, calling it "the most stupid thing I ever heard", it caused an understandable stir.

He directed his words to a Prime Minister who has been consistently bullish on the Iranian issue, but he did not stop there. Last week he urged the country's leaders to seize the initiative by forging a peace deal with "pragmatic Sunni" governments in the region and build on that with an agreement with the Palestinians.

Perhaps the most damning sentence was his observation that "there is shallowness in the debate over Israel's security challenges, they are all being dealt with in slogans. I don't dispute the authority of the Prime Minister and Defence Minister, they are responsible, but I have already said that sometimes, brains and good decision-making are not connected with being elected."

What was Dagan getting at? The Prime Minister's supporters have since accused him of being frustrated at not getting an unprecedented ninth year as Mossad chief. But Dagan is only one of three senior security chiefs who have recently left public service. And while former IDF chief of staff Gabi Ashkenazi and retired Shin Bet head Yuval Diskin have yet to speak out, in the last few months, in closed discussions, they have criticised the lack of diplomatic initiative from the government, and the fear that pressure on the Palestinian front will push the politicians into panicky action against Iran.

Ehud Barak has accused Dagan of "damaging Israel's deterrence" with his remarks, but the discord within the country's highest security echelon over Iran has long been an open secret. Others have accused Dagan of having political ambitions, but for now there is a growing consensus within senior security and diplomatic circles that he is voicing legitimate concerns.