アングロ＝イラク戦争
Quinan could also not contemplate any move north for three months on account of the flooding of the Tigris and Euphrates. Directives were issued to Quinan prior to his assuming command. On 2 May, he had been directed as follows: "(a) Develop and organise the port of Basra to any extent necessary to enable such forces, our own or Allied, as might be required to operate in the Middle East including Egypt, Turkey, Iraq, and Iran, to be maintained. (b) Secure control of all means of communication, including all aerodromes and landing grounds in Iraq, and develop these to the extent requisite to enable the Port of Basra to function to its fullest capacity." Quinan was further instructed to "begin at once to plan a system of defences to protect the Basra Base against attack by armoured forces supported by strong air forces, and also to be ready to take special measures to protect: (i) Royal Air Force installations and personnel at Habbaniya and Shaiba.
On 29 April, having sailed from Bombay, the remaining elements of the 20th Infantry Brigade arrived at Basra on the three transports of Convoy BN1. On 30 April, when Rashid Ali was informed that ships containing additional British forces had arrived, he refused permission for troops to disembark from them and began organising for an armed demonstration at RAF Habbaniya. He did this while fully expecting German assistance would be forthcoming in the guise of aircraft and airborne troops.
On 23 May, Wavell flew to Basra to discuss further reinforcements and operations in Iraq with Auchinleck. Additionally, he instructed Quinan, commanding the Indian forces there, to make plans for an advance from Basra towards Baghdad. On 27 May, the forces from Basra started to advance northwards. In Operation Regulta, the 20th Indian Infantry Brigade, known as the "Euphrates Brigade", advanced along the Euphrates by boat and by road. In Operation Regatta, the 21st Indian Infantry Brigade, known as the "Tigris Brigade", advanced up the Tigris by boat to Kut.
(ii) The lives of British subjects in Baghdad and elsewhere in Iraq. (iii) The Kirkuk oilfields and the pipe line to Haifa." Lastly, Quinan was directed "to make plans to protect the Anglo-Iranian Oil Company's installations and its British employees in South West Iran if necessary." Quinan was informed that "it was the intention to increase his force up to three infantry divisions and possibly also an armoured division, as soon as these troops could be despatched from India."
One plane sustained such heavy small-arms fire that it crashed on the way home, killing the pilot. That evening, 40 trucks armed with machine guns arrived at the fort to reinforce the garrison. Half of the trucks were irregulars under the command of Fawzi al-Qawuqji and the other half were Iraqi Desert Police. Glubb decided to withdraw the troops back to H3 to await the reinforcement of the main column.
The Arab Legion returned to H3 on the morning of 10 May, and found No. 2 Armoured Car Company RAF under Squadron Leader Michael Casano waiting there. They had been sent up ahead of the main column to assist the Arab Legion in taking Rutbah. Casano took his RAF armoured cars to Rutbah whilst the Arab Legion replenished their supplies at H3.