Although the action at Katia boosted Ottoman morale, it soon became clear that it had not deterred the British from continuing their offensive into the Sinai. The railway and the water pipeline made steady, if slow, progress, allowing Murray to move more men forward. In mid-1916 the German Chief of Staff of the Ottoman VIII Corps, Friedrich Kress von Kressenstein, wanted to launch another attack against the British. This time the objective would be the destruction of the railhead, not just the defeat of the forces defending it. Kressenstein assembled 16,000 men for this task. They included the Ottoman 3rd Infantry Division, which had been battle-hardened at Gallipoli, and four batteries of German and Austrian heavy artillery.
The size of this force and the inclusion of heavy artillery meant that it was unlikely to surprise the British troops guarding the railhead, which had by now reached Romani. Every time areas of soft sand were encountered cumbersome and time-consuming measures, such as the laying of wooden planked ‘roads’, were needed to get the heavy guns across. This slowed the Ottoman force to little more than a crawl. Kressenstein was willing to gamble that the extra firepower he could bring to bear would more than make up for a lack of surprise.
Sure enough, the British had ample warning of the Ottoman attack. An aerial reconnaissance flight carrying the commander of the New Zealand Mounted Rifles Brigade, Brigadier-General Edward Chaytor, discovered the Ottoman force on 19 July. It would take another two weeks for the Ottoman troops to reach their target. In the meantime the British reinforced their positions around Romani, bringing up their own artillery by rail to give the defenders 36 howitzers and field guns. Four well-entrenched British infantry brigades directly protected the railhead, while the Anzac Mounted Division occupied the high ground just south of Romani in anticipation of an Ottoman attempt to outflank the defences. As it happened this mirrored the Ottoman plan of attack perfectly.
The Ottoman Turks launched their assault on the night of 3 August 1916. They attempted to outflank Romani from the south with the bulk of their troops, while a smaller force of infantry, supported by the heavy artillery, kept the British defenders pinned down. The Ottoman flank attack ran headlong into the 1st Australian Light Horse Brigade and a vicious close-quarters battle ensued. In the early hours of 4 August Turkish infantry and Australian Light Horse troopers shot and bayoneted each other in the darkness. Despite dogged defence the Australians were eventually pushed back as superior Ottoman numbers began to tell. With Australian positions falling one by one, the commander of the Anzac Mounted Division, General Harry Chauvel, refused to commit the 2nd Australian Light Horse Brigade to the battle until dawn clarified what was happening. When first light revealed the precariousness of the situation, the brigade – which at this time included the Wellington Mounted Rifles Regiment – was immediately ordered to join the fight and help stabilise the line.
Later that morning the New Zealand Mounted Rifles Brigade (which had been kept in reserve), together with two squadrons of the reconstituted British 5th Mounted Brigade, launched a counter-attack. By midday British infantry reinforcements from Kantara were beginning to arrive by train at Pelusium station (the last stop before Romani). By 2 p.m. the New Zealanders were in position and launched their attack, concentrating on a sandhill in Ottoman hands known to the troops as ‘Mount Royston’. With virtually no natural cover to protect them from Ottoman fire, the initial New Zealand attack got bogged down. But a renewed assault in the early evening saw the New Zealand horsemen, supported by British yeomanry, capture Mount Royston, taking 500 prisoners and overrunning a battery of Ottoman artillery.
The Ottoman line now began to unravel. Renewed attacks by the Australian Light Horse and British infantry forced the Ottoman force into a general retreat by nightfall. The Ottoman diversionary attacks and bombardment of the British infantry positions at Romani had failed to make any impact. Attempts to destroy the remainder of the Ottoman force the following day, though, were only partially successful. The British infantry could not catch the retreating Ottoman troops and the New Zealand and Australian horsemen were in no fit state to mount a pursuit after bearing the brunt of the fighting the day before. The Ottoman force suffered 5000 casualties, of whom 4000 were taken prisoner. Most of the 1130 Allied casualties were suffered by the Anzac Mounted Division.