Efforts to oust "evil" Syrian president Bashar Assad have reached a stalemate, Prime Minister David Cameron acknowledged as he insisted it was right to continue efforts to support the rebels despite fears over the presence of al Qaida-linked elements within the opposition movement.
Mr Cameron said the situation in Syria was "on a depressing trajectory" with Assad's position getting stronger, but stressed that no decision had been taken about whether to supply weapons to moderate opposition forces in an effort to tip the balance back in their favour.
He denied reports that his wife Samantha had pushed him to take a more proactive stance after witnessing at first hand the humanitarian disaster caused by the bloodshed in Syria.
Appearing on BBC1's Andrew Marr Show, Mr Cameron said the situation in Syria was a "very depressing picture and it's a picture that is I think on the wrong trajectory".
There was "too much extremism amongst some of the rebels" and "appalling behaviour from this dreadful regime using chemical weapons".
He said: "We do need to do more to help promote those parts of the opposition that want a free, pluralistic, democratic Syria. And so we're not arming the rebels. We have made no decision about that."
But he added: "It's no good complaining about the rebels if you're not going to try and help those that want a free, democratic, pluralistic Syria.
"And that's why we're helping with non-military equipment, we're helping with technical assistance and training, we're working with other like-minded countries, including those in the region, to help those who want a democratic Syria. And that's the right thing to do."
Mr Cameron said Assad was an "evil president who's doing dreadful things to his people" and accepted he was gaining in strength over the opposition.
He said: "I think he may be stronger than he was a few months ago, but I'd still describe the situation as a stalemate."