British special forces have been operating on the ground in Iraq for six weeks, it has emerged, as David Cameron retreats from a larger military involvement.
Baroness Nicholson of Winterbourne, who serves as Britain's trade envoy to Iraq, broke the government's default silence on the SAS' activities to the Telegraph.
There is now speculation about whether the SAS on the ground could assist the small force of American soldiers who briefly landed on Mount Sinjar to liaise with the Yazidis, who have been besieged by Islamic State extremists.
Plans to save the trapped Yazidis have been put on hold after the Americans backed away from going ahead with the rescue operation.
Intelligence confirming there are only about 5,000 stranded people on the mountainside, which is now well-supplied with humanitarian aid, has made Barack Obama's administration reluctant to order the rescue mission.
It reduces the likelihood that the British Chinook helicopters being sent into northern Iraq will be used to rescue the Yazidi refugees.
Yesterday Cameron ended his first day back after a shortened summer holiday with an evening of intense telephone diplomacy, including a phone call with Kurdish leader Barzani.
"The prime minister commended the bravery of the Peshmerga forces and President Barzani updated the prime minister on the progress they had made on the ground," a Downing Street spokesperson said.
"The prime minister underlined the UK's role in helping international partners transport critical military supplies to the Kurdish forces and said that the UK would continue to do all it could to provide humanitarian support, including identifying ways to strengthen capacity at the Dahuk refugee camp."
With a recall of parliament ruled out for now, frustrated Conservative MPs have been voicing their demands for the government to do more.
Yesterday former defence secretary Liam Fox undermined Cameron's approach by criticising the "catastrophic complacency" of western politicians in not responding robustly enough to the crisis.
And today Mark Field wrote in an article for ConservativeHome that the Kurdish minority in Iraq deserved the urgent support of Britain.
"If UK involvement is to extend beyond intelligence cooperation and humanitarian help, our government will need to level with the British public now about the potential extent of our future involvement," he wrote.
"UK airstrikes, drone attacks and the arming of and military support to the Peshmerga may follow within weeks."
Over one million people are displaced across northern Iraq, prompting the declaration of the highest possible level of humanitarian crisis by the United Nations.