Hague met with Arab League Secretary-General Nabil el-Araby in London. Hague's office said the officials discussed the civil war in Syria and noted they were in support of political steps needed to bring about an end to the conflict.
Hague, in a statement, said the British government believes Assad has lost his legitimacy to lead the Syrian people.
"His latest promises of token reforms demonstrate his increasingly desperate attempts to hold on to power," he said.
Assad, in a televised speech last weekend, said peace would come to his country once regional powers stopped supporting an opposition movement threatening his regime. He said the army would then halt all military operations but would reserve the right to defend state interests, the BBC reported.
Victoria Nuland, a spokeswoman for the U.S. State Department, said Washington felt Assad was out of touch with reality.
"I don't think anybody who is guilty of the kinds of crimes against your own people that he's guilty of can be considered rational by any human sense of the word," she said.
The United Nations estimates at least 60,000 people have died as a result of the war, which began in early 2011.