The Foreign Secretary refused to rule out the prospect that Britain could arm the Syrian rebels, despite a warning from President Bashar Assad that supplying weaponry to the opposition could ignite a conflict across the entire Middle East.
Mr Hague – who is set to announce further non-lethal assistance to the rebels later this week – dismissed the Syrian leader as “delusional”.
He said that the UK would continue to step up support for the opposition as long as there was no diplomatic or political breakthrough in the two year long conflict.
“The longer this goes on the greater the danger that extremism takes hold, the greater the danger of destabilising neighbouring countries, and the greater the extreme humanitarian distress involved. So we cannot just sit on the sidelines and watch this,” he told BBC1’s The Andrew Marr Show.
“We will be doing more and we will have to steadily do more if there is no diplomatic or political breakthrough. The situation in Syria now is too dangerous to the peace and security of that entire region and thereby to the world to ignore it.
“I don’t rule anything out for the future. If this is going to go on for months or years and more tens of thousands of people are going to die and countries like Iraq and Lebanon and Jordan are going to be destabilised it is not something we can ignore.
“These are the reasons why we can’t just sit it out in Syria.”
Mr Hague, MP for Richmond, North Yorkshire, acknowledged that one of the reasons Britain had not been prepared to supply arms to the rebels was the danger they could fall into the hands of Islamist extremists, but he said that could change.
“These things are a balance of risk. You can reach the point eventually and the loss of life is so great that you have to do something new to save lives,” he said.
His comments came after Assad used an interview with The Sunday Times to denounce Britain’s “naive, confused and unrealistic” approach to the conflict and to insist it had no role in any solution.
“We do not expect an arsonist to be a firefighter,” he said.
“To be frank, Britain has played a famously unconstructive role in our region on different issues for decades, some say for centuries... The problem with this government is that their shallow and immature rhetoric only highlights this tradition of bullying and hegemony...
“How can we ask Britain to play a role while it is determined to militarise the problem?
“How can we expect them to make the violence less while they want to send military supply to the terrorists?”
Mr Hague said Assad appeared to have been convinced by his inner circle that the uprising against him was the result of an international conspiracy which had nothing to do with the Syrian people.
The US Secretary of State John Kerry announced on Thursday that the Obama administration was giving an additional £40m in assistance to Syria’s political opposition and would, for the first time, provide non-lethal aid directly to the rebels.
In their first official statements on the US decision, the Syrian and Iranian foreign ministers yesterday accused Washington of having double standards and warned it would only delay an end to the civil war. Iran is a staunch ally of the Syrian regime.