News that UK Special Forces are now operating in Northern Iraq raises some significant questions about Britain's mission in the country.
The SAS is understood to be in the Sinjar mountains "scoping the ground" in case world leaders decide to embark on a major international rescue operation later in the week.
The Ministry of Defence has sent four RAF Chinook helicopters to the area. The first two arrived at the British base in Cyprus last night.
It's believed they will soon be deployed to Turkey - which shares a border with Iraqi Kurdistan - from where the Chinooks can carry out their humanitarian mission.
The Prime Minister spoke to the President Erdogan of Turkey on Wednesday night, presumably to request permission to fly UK military helicopters in his airspace.
Any Chinook pilot would be relieved to know that the SAS have been surveying a mountain surrounded by fundamentalist fighters on which he/she is expected to land.
But with the deployment of Special Forces on Mount Sinjar, can the British government still legitimately claim this is a humanitarian - not a combat - operation?
Many MPs are asking David Cameron to recall Parliament so that these issues can be debated.
The demand to bring MPs back from their summer recess was brushed away by Mr Cameron's spokesperson at the start of the week.
Since then the deployment of Tornado jets, Chinook helicopters and SAS forces have been confirmed.
As that military hardware and personnel masses in the region - when does this mission change to one of combat?