David Cameron has suggested Syrian President Bashar al Assad should be spirited out of the country to avoid any further bloodshed.

The Prime Minister said it "could be arranged" for Mr Assad to leave Syria, potentially escaping international justice over his regime's bloody repression.

His comment overshadowed the second day of a trip to the Middle East to attempt to secure deals for British business.

Mr Cameron has faced intense criticism for taking a group of arms dealers to the region.

He made it clear the UK would not offer Mr Assad a haven, but raised the prospect of an arranged exit ahead of talks with King Abdullah of Saudi Arabia.

Asked what he would say if President Assad said he wanted safe passage, Mr Cameron told Al Arabiya television: "Done. Anything, anything to get that man out of the country and to have a safe transition in Syria.

"Of course, I would favour him facing the full force of international law and justice for what he's done.

"I am certainly not offering him an exit plan to Britain but if wants to leave, he could leave, that could be arranged."

Mr Cameron also ruled out the possibility of arming Syrian rebels, but said the UK would increase its humanitarian aid as he said he was "frustrated" that the international community had not done more to prevent the deaths of up to 40,000 people.

"We must ask ourselves what more can we do? How can we help the opposition?" he said.

"How can we put the pressure on Assad? How can we work with partners in the region to turn this around?"

Downing Street said that while Britain wanted President Assad to face justice, the "top priority" was to get him out of the country to enable political transition to take place.

"We want Assad to face the full force of inter-national law for what he has done but our top priority is to see transition in that country," the Prime Minister's spokesman told reporters in London.

"That transition cannot happen while Assad remains in place and therefore we want him to go."