'Ophelia' was a British undertaking to move forces from Palestine to Iraq (May 1941).

On 18 May Brigadier J. J. Kingstone’s 'Kingcol', the flying column of Major General J. G. W. Clark’s 'Habforce' relief force, reached and relieved the British base at Habbaniyah outside Baghdad. 'Habforce' (Habbaniyah Force), assembled in Palestine by General Sir Archibald Wavell, the British commander-in-chief in the Middle East, was commanded by Clark, who was already the commander of the 1^st Cavalry Division comprising Brigadier J. J. Kingstone’s 4^th Cavalry Brigade, Brigadier K. F. W. Dunn’s 5^th Cavalry Brigade and Brigadier G. H. N. Todd’s 6^th Cavalry Brigade.

The 1^st Cavalry Division, stationed in Palestine for some time, had been steadily stripped of much of its artillery, engineers, signals and transport to provide for the needs of other formations in Greece, North Africa, and East Africa. Thus a mere one motorised cavalry brigade could be provided for fast movement over longer distances, and this only by pooling the division’s entire motor transport strength.

It was after the Trans-Jordan Frontier Force refused to enter Iraq, whereupon it was disarmed, that Clark decided to divide 'Habforce' into two columns, the first of them a flying column known as 'Kingcol' (King Column) and comprising the 4^th Cavalry Brigade, two companies of the 1/Essex, No. 2 Armoured Car Company RAF, and a battery of 25-pdr gun/howitzers of the 60^th Field Regiment. The second column was the 'Habforce' main force, under Lieutenant Colonel J. S. Nichols, and comprised the remaining elements of the 1/Essex, the remainder of the 60^th Field Regiment, one anti-tank battery, and ancillary services. In addition to 'Kingcol' and the 'Habforce' main force, Clark could call on a 400-man detachment of the Arab Legion. The Arab Legion consisted of three mechanised squadrons transported in a mixture of civilian Ford trucks and equipped with home-made armoured cars. Unlike the Trans-Jordan Frontier Force, the Arab Legion was not part of the British army but an element of the army of Transjordan and commanded by Lieutenant General J. B. Glubb, also known as 'Glubb Pasha'.

During the morning of 11 May, 'Kingcol' left Haifa on the coast of Palestine under orders to reach Habbaniyah as quickly as possible. This was the last all-horse undertaking in British military history. On 13 May 'Kingcol' reached in Rutbah in north-western Iraq but found no opposition. Glubb and the Arab Legion had already moved on, but 'Kingcol' required maintenance before advancing from Rutbah. On 15 May the column made it first contact with the Iraqis when a Bristol Blenheim bomber strafed the column and dropped a bomb, but suffered neither damage nor casualties. On 16 May further bombing attacks were made against the column when it was attacked by German aircraft, and on this occasion there were a few casualties.

During the late evening of 17 May 'Kingcol' reached the area of Habbaniyah, and on the morning of the next day the column entered the RAF base, the remainder of the 1/Essex being airlifted into the base during the rest of the day, lifting the Iraqi threat to the base.