Syrian president Bashar al-Assad is not a dictator - just a figurehead - according to a former British ambassador to Syria.

Sir Andrew Green's remarks in the Spectator are likely to enrage critics of Assad's regime at a time when David Cameron is discussing whether to follow the US decision to arm rebels in Syria.

In a blogpost entitled "If you think arming the rebels is the answer, then you don't understand Syria", Green, the former diplomat and founding chairman of the organisation MigrationWatch UK, criticised the "spin generated by Number 10 in recent days".

"All this spin reflects a fundamental failure to understand the nature of the situation in Syria," he argued. "Bashar al-Assad is a figurehead, not a dictator on the pattern of Saddam Hussein, or even his [Assad's] father.

"What some outside observers fail to realise is that the Alawites, having run a very tough police state for 40 years, simply cannot afford to lose power," he said.

"If they were to do so, they believe that they and their families would be massacred. They may well be right."

Green has published a series of commentaries against arming the Syrian rebels.

"I have met both Bashar al-Assad and his father, Hafez, from whom he took over as president. His father was terrifying - utterly ruthless and a conspirator to his finger tips," he wrote in the Telegraph.

"The young Assad, Bashar, is nothing of the kind. Those who knew him well when he was training as an opthalmologist in Britain report a pleasant, well-mannered and quietly professional young man. Back in Damascus, after his father's death, he was not much more than a figurehead president."

Green was also co-chairman of the British Syrian Society (BSS), founded by Assad's father-in-law, cardiologist Fawa Akhras.

Akhras came under fire in 2012 for an array of leaked emails published by the Guardian that showed him giving advice to Assad on how to manage the Syrian crisis while his daughter Asma, the president's wife, went shopping for luxury goods.

After the scandal broke, Green resigned. The BSS had been in crisis since the uprising began in 2011.

At least 93,000 people have been killed and more than 1.5 million have fled the country to take refuge in neighbouring countries in the two-year conflict.