Samantha Cameron 'not shaping' Syria policy, says No 10
No 10 has downplayed reports Samantha Cameron has been a major influence on her husband's policy towards Syria.
The prime minister's wife met some of those caught up in the two-year conflict during a visit to a refugee camp in neighbouring Lebanon in March.
Citing senior government sources, The Times reported she had since pushed for a bolder humanitarian response.
But Downing Street said British policy towards Syria was decided by the National Security Council.
The UK has given £348m in humanitarian aid, including food and medical supplies, to those affected by the fighting in Syria as well as the thousands made homeless by the conflict and living in camps in Lebanon, Jordan, Turkey and Iraq.
David Cameron led calls for the EU arms embargo on the Syrian opposition to be lifted although The Times claimed that the prospect of the UK providing weapons - a move opposed by many Conservative MPs - was receding.
'Hardly worth it'
Mrs Cameron visited the refugee camp in her role as an ambassador for Save The Children earlier this year.
After visiting a treatment centre for children traumatised by the conflict, she said the stories she had heard were "harrowing" and "with every day that passes, more children and parents are being killed, more innocent childhoods are being smashed to pieces".
The Times said a Cabinet minister had told the newspaper that Mrs Cameron was the "biggest explanation" for the prime minister's stance on Syria, regarded to be the most hawkish in Europe.
Asked about Syria at the daily lobby briefing, a No 10 spokesman said reports of Mrs Cameron's input should be treated "with a fair bit of caution" and insisted policy on Syria was driven by the National Security Council.
Although the UK succeeded in its effort to lift the embargo, no weapons have been sent and Conservative MPs have demanded a parliamentary vote before any decision is taken amid concerns armour will fall into the hands of extremists.
The government has said its main focus is on diplomatic efforts to secure a ceasefire.
But ministers have also suggested that changing the balance of military power on the ground - which has swung in favour of forces loyal to President Assad in recent months - could help accelerate an eventual political transition.
But the Times reported that armed forces chiefs had told ministers last month that although providing arms to moderate opposition forces "might make people feel better", it was "hardly worth it" in terms of altering the state of play on the ground.
Downing Street said the National Security Council continued to "examine all the options closely".
Separately, The New York Times claimed that many officials in Washington believed any assistance the US provided was unlikely to be sufficient to force President Assad into negotiations.
The newspaper said plans for the CIA to covertly train and arm the rebels were much more limited than indicated by the Obama administration and could take months to have any effect.