The division was not concentrated until mid-March 1918, and when it moved north up the Tigris, 53rd Brigade was left behind to subdue Nejef, south of Baghdad. After making a forced march of nearly 90 miles in a week through almost waterless country and carried out a demonstration, the brigade was being withdrawn when trouble flared up again. The town was then blockaded from 21 March to 19 May, with the 9th Middlesex being involved in minor actions. The battalion celebrated Albuera Day in the Mesopotamian desert. 53rd Brigade then rejoined the division at Akab, near Samarra. Summer weather made campaigning impractical in Mesopotamia, so the division was engaged in roadbuilding until the beginning of October, when orders were received to join the renewed advance up the Tigris.