Ottoman forces abandon Es Sinn

On the morning of 19 May 1916 British aircraft reconnoitring the Turkish positions on the right bank of the Tigris below Kut reported a large enemy withdrawal. The trenches at Beit Aiessa and Chahela, which the British had fought for in April, were empty, and the camps by the Es Sinn embankments had vanished. The Turks still held the Sinn Abtar redoubt and the bridge of boats over the Tigris at Abd al-Hasan, and on the left bank they still held the Sannaiyat position in strength. The British chronology of the war says that the Turkish army abandoned the Es Sinn position and fell back to Kut. According to the British official history (Moberly, The Campaign in Mesopotamia, vol. III), the Turks took up a line on the Shatt al-Hai, the channel that leaves the Tigris opposite Kut, and occupied it from the town southwards.

The cause of the withdrawal was not British pressure but the Russians. After the surrender of Kut, the commander of the Ottoman Sixth Army, Halil Pasha (Halil Kut), moved to Baghdad. He was sure the British would not break through his defences on the Tigris, but he was worried by the Russian corps of General Nikolai Baratov, which on 7 May had taken Qasr-e Shirin on the Persian–Ottoman border and threatened Baghdad from the east. According to Turkish data cited by Moberly, in the second week of May Halil began transferring a cavalry brigade and the 2nd Division from the Tigris to the Persian border near Khanaqin, together with the newly arrived 6th Division. According to other accounts, it was Enver Pasha, who came to Baghdad in May, who demanded that the whole XIII Corps be moved to the Persian border. The exhausted 35th Division was disbanded. Only the three divisions of XVIII Corps were left facing the British. General George Gorringe estimated the Turkish forces below Kut at about 20,000 men, two-thirds of them on the right bank. According to German and Turkish sources there were only 11,000–12,000.

The Tigris Corps, however, was in no state to exploit the opportunity. After the failure of the relief it was exhausted, and the months of the worst heat were coming. In April and May about 800 cases of cholera were recorded in it, and on 14 May Gorringe reported that command of the air had passed to the Turkish Fokkers. When the first reports from the airmen came in, Gorringe was visiting Sheikh Saad. The senior general at the front, Keary, sent out the 33rd Cavalry to reconnoitre at about 8.30 and ordered the infantry to occupy the abandoned trenches at Beit Aiessa and Chahela. Two hours later Gorringe countermanded the order. Because of the heat, the lack of water and fear of cholera in the abandoned trenches, he decided to move only at night, bypassing them well to the south, and to seize the Turkish bridge at Abd al-Hasan at dawn.

On the morning of 20 May the cavalry found that the Turks had already dismantled the bridge. Shortly before ten the infantry of Keary’s 3rd Division occupied without a fight the Dujaila redoubt, against which Aylmer’s attack had broken in March. The march in the heat across the waterless plain was deadly, however. The soldiers’ water bottles ran dry, exhausted stragglers lay along the whole route, and some of them died of heat. On 21 May the cavalry approached the bridge over the Shatt al-Hai near Kut, but ran into entrenched infantry with artillery and turned back. Keary reported that taking the line of the channel would require at least a whole division, and that his men were too tired. The British halted on a line from Magasis on the Tigris to Dujaila.

For the following weeks London, Simla and Basra discussed whether the Tigris Corps should cross the river and outflank Sannaiyat to relieve Baratov, but Gorringe judged that it could not be done without heavy losses. The Turkish forces, reinforced in this way, repulsed Baratov’s attack at Khanaqin on 1 June and forced him to retreat deep into Persia. The front on the Tigris went quiet for half a year. The British advanced on Kut again only in December 1916.