By Alex Stevenson Follow @alex__stevenson
Britain and other western states should bring the Syrian crisis "to a head" by imposing a full economic embargo, former foreign secretary Sir Malcolm Rifkind has said.
Writing for politics.co.uk, the ex-defence secretary called for "concerted international action" to undermine the regime's grip on Syria.
An international military intervention is extremely unlikely given Russia and China's deep opposition to such a move, but this does not "eliminate the international community's options", Sir Malcolm wrote.
"Starting immediately, the Arab League, Turkey, the US and EU should move to establish a full economic embargo," he urged.
"Such a step would have an inevitable effect on the Syrian people. Yet it would bring the situation to a head, and prevent their suffering being prolonged."
Sir Malcolm said an embargo would be "difficult, but not impossible" to impose.
Syrian trade would have to be blocked by shutting down its land borders with Turkey and Iraq, while a naval blockade and "rigorous searches" of vessels bound for Lebanon could prevent the regime receiving shipments of arms from Russia and Iran.
Bashar al-Assad's forces continued their bombardment of the besieged city of Homs yesterday.
At least 16 people are thought to have been killed in Tuesday's attacks, adding to a death toll which has seen over 6,000 civilians lose their lives in the last year.
"The argument that Assad brings stability to a trouble region has been demolished by recent events," Sir Malcolm added.
"The country is mired in a civil war, made possible by the desperation of the regime, and a small group of foreign enablers.
"Cutting off their support and bringing down the regime would be good for Syrian people, and the region as a whole. We should not delay."
US officials have indicated they would prefer a political solution to the Syrian crisis, which is threatening to descend into an all-out civil war. But they have said they are prepared to consider "additional measures" if Assad does not back down soon.
Sir Malcolm is the latest in a series of senior Tory backbenchers to demand action against Syria.
Foreign affairs committee chair Richard Ottaway told politics.co.uk earlier this month: "There are still a number of nations in the world who are very hesitant about the policy of intervention - they tend to be the more autocratic regimes like China and Russia.
"We have to accept there is a norm by which we conduct life on this planet and that norm is not being followed in Syria at the moment."