1 (UK) Division was given the task of isolating Basra. 3 Commando Brigade held the Al Faw peninsula and Umm Qasr, the 16 Air Assault Brigade held the oilfield at Rymayalh which tied down the Iraqi 6th Armoured Division which was north of Basra, preventing it from interfering.
 

7th Armoured Brigade held brigades over the Shatt-Al-Basrah waterway to the west of Basrah, while under constant attack from conventional and irregular Iraqi forces. As such 7th Armoured Brigade protected the right flank of the US advance on Baghdad. Other elements of the Brigade came under fire from irregulars in and around Az Zubayr. British troops were attacked by machine gun and rocket fire when they neared the town. The Brigade replied with intelligence-guided precise strikes and raids into the town against regime supporters.

The Brigade set up checkpoints around Az Zubayr controlling movement in and out of the town, as well as points from which humanitarian aid could be distributed and operations launched. From the south, 3 Commando Brigade advanced to secure Abu Al Khasib, 10 kilometres southeast of Basra. The brigade met stiff resistance in some areas where firefights and hand to hand fighting took place between 30th March and 3rd April until the area was secured.

By 1st April, the Brigade held the town of Az Zubayr, the irregulars having fled or been killed or captured. Similar operations all around Basra coupled with air and artillery strikes against regime targets gradually eroded the regime's ability to control the city.

A series of raids on 4th and 5th April reduced the Ba'ath leaderships ability significantly coupled with the knowledge that UK troops patrolled openly in liberated towns, and US forces threatened Baghdad. With these conditions, UK forces entered Basra on 6th April, quelling some resistance by both conventional and irregular Iraqi forces.