Israel's secret service, the Mossad, is regarded as one of the most resourceful and ruthless intelligence agencies in the world.

But are Israel's top spies on the same page as the country's politicians when it comes to an assessment of the threat posed by Iran?

The question was prompted by Meir Dagan, director of Mossad until a year and a half ago. Just months after retiring he said an Israeli strike on Iran's nuclear facilities would be stupid.

Why did he go so public so quickly, and is there a dangerous gulf between Israel's political leadership and security chiefs?

(Image: Meir Dagan - left - shakes hands with former Prime Minister Ariel Sharon while receiving his letter of appointment in October 30, 2002. Credit: Getty Images)