The planning and the military action to retake Mosul from Islamic State has in reality been going on for months now.
US-led coalition jets have targeted IS positions in and around the city while the Iraqi army, retrained and rearmed after their calamitous capitulation to the jihadists in the summer of 2014, have been advancing through villages and towns towards the country’s second city.
But the progress has been piecemeal and incremental. For two years I have visited some front line positions that have not moved a single inch.
The announcement that the offensive to reclaim Mosul is under way is designed to indicate that after intense negotiation a multi-faceted multi-ethnic force is united in one goal to remove IS.
Their sheer numbers and the likelihood of a mass exodus when the fighting intensifies, complicates military action and poses serious logistical and humanitarian questions: how to protect the displaced and where to put them, the most pressing.
The old military adage, remember the enemy has a point of view as well, couldn’t be more appropriate.
Islamic State is believed to have fighters in their thousands – 4,000 seems a reasonable working figure.
Well dug in, it is assumed they have laid IEDs and booby trapped buildings, even streets, while ruling the city for two years.
Kurdish Peshmerga fighters keep watch during the battle with Islamic State militants on the outskirts of Mosul
They have done so in the past and Mosul, the largest population centre under their control, has been something of a prize and arguably something worth trying to hold on to.
Even if they were to decide it is an unwinnable battle, it certainly doesn’t mean there will be a peaceful solution – quite the opposite.
So in real terms the Mosul operation is a major challenge before we even consider the myriad fighting groups represented in the Mosul task force, many of whom are only ever one step from openly fighting each other.
The lead will be taken, unsurprisingly, by the Iraqi forces with their own and United States special forces.
A member of the Kurdish Peshmerga forces stands guard at a security point on Bashiqa mountain, overlooking Islamic State held territories of Mosul
Two Sunni militia groups in the immediate region can easily muster 10,000 men and will be used, but they are fierce rivals and are already vying for power in the liberated Mosul.
The Kurdish Peshmerga and the elite Counter Terrorism Group are determined to be involved and are needed.
But Kurdish eagerness to strengthen control in predominantly Arab regions is a concern for Baghdad.