Direct proof of use
Royal Navy history for HMS Brocklesby records the Hunt-class vessel among the first coalition ships into Umm Qasr during operations in Iraq and credits it with clearing a mined channel into the port. Contemporary Voice of America reporting from March 26, 2003 identified Brocklesby and USS Dextrous as the two ships clearing a 200-meter channel through the final stretches of the port area.
The UK Ministry of Defence lessons chapter for Operation TELIC, mirrored by GlobalSecurity, gives the operational detail: HMS Brocklesby led the initial surface mine countermeasures group controlling SWIMS while other mine countermeasure vessels relocated, detected, and destroyed mine-like contacts to widen the channel.
Sources: Royal Navy HMS Brocklesby, VOA Umm Qasr Demining, UK MoD Iraq Maritime Lessons
Timeline
Mine-countermeasure operations began immediately around the opening of the invasion, with U.S., U.K., and Australian mine-warfare and explosive-ordnance teams working while ground fighting continued near Umm Qasr. USNI Proceedings listed HMS Brocklesby among the British mine countermeasure ships operating with U.S. minesweepers in the Khawr Abd Allah waterway.
By March 26, VOA reported Brocklesby and Dextrous were clearing the channel for the expected passage of RFA Sir Galahad, which was carrying food, water, sugar, lentils, and other relief supplies. The UK lessons account states that the first breakthrough to Umm Qasr took four days, followed by route-widening and clearance; on March 28 HMS Sandown led RFA Sir Galahad to Umm Qasr with humanitarian aid.
Sources: USNI Mine Countermeasures, VOA Umm Qasr Demining, UK MoD Iraq Maritime Lessons
Narrative
Brocklesby's role was maritime mine clearance rather than shore attack. The vessel operated as part of a broader coalition mine-countermeasure effort to open the Khawr Abd Allah approach and Umm Qasr port area after Iraqi minelayer threats, suspected seabed contacts, silt, poor visibility, and fighting ashore made the route hazardous.
The documented effect of the Hunt-class vessel's work was access: Brocklesby helped clear and widen the mined channel so larger coalition and relief vessels could safely use the port. Sources identify the platform as Royal Navy-operated and place the mission on the coalition side of the 2003 Iraq War.
Sources: Royal Navy HMS Brocklesby, USNI Mine Countermeasures, UK MoD Iraq Maritime Lessons