He was not due back until later tonight and not back at the coal face until tomorrow.
But plans have been shunted forward 24 hours to enable the Prime Minister to chair this afternoon's emergency meeting in Whitehall over Iraq.
The government has been operating against the backdrop of criticism for its rudderless approach to the humanitarian crisis unfolding on the Sinjar Mountains in northern Iraq.
The UK has so far refused to get involved militarily - and is not joining US airstrikes on targets of the Islamic State (ISIS).
But the Foreign and Defence Secretaries have authorised the deployments of RAF Chinook helicopters and RAF Tornado jets to join the military hardware now congregating in the eastern Mediterranean.
The Chinooks will arrive at the British base in Cyprus later today.
Number Ten has insisted throughout that the Prime Minister has been in charge and across all developments while on his family holiday in Portugal.
But when the suffering in Iraq is so great - and thousands of people have fled for their lives - there is nothing like seeing David Cameron back in Downing Street to show that he does care about this crisis and he is acting to alleviate the misery of so many.