On the 29th April 1941, over 250 women and children were evacuated from Baghdad to Habbaniyah because of the worsening security situation in the city. Later in the day, large numbers of Iraqi Army began to move westwards, reported by the British Embassy in the city, to the base. By 03:00hrs on the 30th 2 brigades of Iraqi infantry had deployed on the high ground to the South of Habbaniyah while a further brigade deployed at Ramadi 16 miles to the West. With the Euphrates levees breached, it meant that the base was effectively surrounded with its back to the river. Simultaneously the oil fields at Kirkuk were seized by the Iraqis and closed and the flow to Tripoli opened effectively switching sides.
The base was now overlooked from the high ground by at least 1000 Iraqi troops with artillery, armoured cars and light tanks, with the full support of the Iraqi Air Force. By the 2nd of May that force had grown to 9000. The Iraqi High Command then informed that all training was to cease and that any flying would bring down artillery fire from the Plateau. Air Vice Marshal Smart informed them that any interference would be classed as an act of war. Smart considered his only chance would be the launch of a pre-emptive strike against his much better equipped and populous enemy. He did so with his tiny force at 5:30am on the 2nd. The action was continuous all day with artillery and air attacks by the Iraqis and further bombing raids by the British. As darkness fell, 1 ACC and the Levies dominated the no mans land with aggressive patrolling. 4 further days of fighting and attrition on both side followed. Reinforcement of the Iraqi troops on the escarpment went ahead and were subjected to further but dwindling attacks by the RAF’s surviving aircraft. On the 6th of May for inexplicable reasons the Iraqis gave up and retreated, streaming away from the plateau, harassed by air attacks and shell fire. Lack of morale caused by lack of supplies and water and reluctance to fight their erstwhile allies took toll of the attackers. The defenders of Sin El Dhibben were more stubborn and it took 2 companies of the Kings Own and Levies, fired in by the armoured cars of 1 ACC, to clear the village. A further large armoured column was destroyed coming from Fallujah from the air and the siege was to all intents and purposes done. 1 ACC reconnoitred the escarpment the next day and its was deserted. The Iraqis had suffered major looses in materiel, captured when they folded their tents, and between 500 and 1000 dead against 13 killed and 21 wounded.