William Hague has called for Syrian President Bashar Assad to reform or step aside.
The Foreign Secretary said the Syrian leader was losing legitimacy.
In an address to the House of Commons, Mr Hague condemned the Syrian regime, which human rights groups blame for the deaths of 1,200 protesters since anti-government uprisings began in the country three months ago.
He also referred to the torture and murder of a 13-year-old boy, Hamza al-Khatib and said that the government had circulated a draft UN Security Council resolution condemning the Assad regime.
Yesterday a number of Israeli politicians, including Deputy Foreign Minister Danny Ayalon, accused Mr Assad of facilitating Sunday's deadly clashes on the Syrian border with Israel.
Mr Ayalon said the Syrian leader had encouraged Palestinian protesters to attempt to cross the border as "cannon fodder", so that he could "divert attention from the carnage that he is wreaking on his people."