All through the winter every movement on the part of the Dervish leaders was carefully watched by the gun-boats on the Nile and the Egyptian cavalry on its banks. The Intelligence Department had a system of espionage by which the feeling inside Omdurman was made known to them. The Sirdar knew that the Khalifa was unwilling to turn out his main army, but that a large force was preparing to move out of Metemma under the combined command of the Emir Mahmoud and the cavalry leader Osman Digna. Before long the Sirdar knew that this force had crossed to Shendy on the right bank of the Nile on February 28, and that on March 13 they had reached Aliab, which is only twenty miles south of Dakila, the Egyptian outpost. But their subsequent designs were not known. It was doubtful whether their scheme was to attack the Sirdar at Dakila, a fort which had recently been built on the right bank of the Nile, where the large tributary stream of the Atbara flows in from the south-east, or to make a dash {199} on Berber and sever the railway communication lower down. Eventually the Dervish leader found himself unable to carry out either of these schemes, the fortress appearing too formidable after the arrival of the British contingent, and Berber proving too remote. He decided therefore to threaten both points, and took up a strong position on the banks of the Atbara, about thirty miles above Dakila, which he fortified and entrenched elaborately, and waited for his foes to take the initiative. The force with which the Sirdar could meet the enemy was composed of the British Brigade, which had now been completed to four battalions by the arrival of the Seaforth Highlanders, and three Brigades of the Egyptian Army, commanded respectively by Colonel Maxwell, Colonel Macdonald, and Colonel Lewis. There were also eight squadrons of cavalry, and two Maxim guns under Colonel Broadwood, six companies of the Camel Corps under Major Tudway, and some artillery, both heavy and light, under Colonel Long. The total ran up to nearly 14,000 men of all arms. This force was concentrated at Kenur on the Nile, and all the officers seem genuinely to have held the opinion that contact with the enemy might occur at any moment. But as it turned out, it was not till seventeen days after the Sirdar's force started on their march to meet the enemy that the two armies met.