Anti-war campaigners told William Hague to look in the mirror after he denounced a speech by Syrian President Bashar Assad as "beyond hypocritical" today.
The Foreign Secretary's outburst came after President Assad's first address to Syria since June.
Mr Assad said that a peace plan, including a national reconciliation conference and a new constitution, could only get under way after Western nations stopped funding and arming rebel groups.
"We never rejected a political solution," he said. "But with whom should we talk? With those who have extremist ideology who only understand the language of terrorism?
"Or should we negotiate with puppets whom the West brought?
"We negotiate with the master not with the slave."
Mr Hague took to Twitter to vent his anger following the speech, writing: "Assad speech beyond hypocritical. Deaths, violence and oppression engulfing Syria are his own making, empty promises of reform fool no-one."
Prime Minister David Cameron had earlier reiterated his calls for the Syrian leader to quit.
But Stop The War's Lindsey German said that Hague and Cameron were in no position to pass judgement.
She told the Morning Star: "William Hague is the last person you'd expect to be crying hypocrisy given his government's track record in the Middle East, which has done more damage in the Middle East than any other government in history.
"The last thing he wants is any kind of settlement.
"Both Hague and David Cameron should look in the mirror when they talk about Assad's blood on his hands when they have the blood of millions on theirs."