In 1999, Marconi Electronic Systems was contracted to upgrade British Army AS-90s to include a 52 calibre gun in order to increase the range of the artillery.

[4] Critical to the programme was a bi-modular charge system from Somchem of South Africa (selected after extensive trials of ammunition from many suppliers), which offered greatly reduced barrel wear.

[5] It remains in UK service and equips three field regiments supporting armoured infantry brigades for the foreseeable future.

[8] On 24 April 2022, the Daily Express reported that AS-90s and 45,000 artillery rounds would be sent to Ukraine[9] but that was subsequently denied by Defence Secretary Ben Wallace.

[10] On 14 January 2023, British Prime Minister Rishi Sunak announced that Britain would send 30 AS-90 to Ukraine, amongst other supplies (including 14 Challenger 2 tanks), for use in the ongoing Russo-Ukrainian War.

The purchase will fill a hole in capabilities until a new system is decided upon as part of the Mobile Fires Platform program, where Archer was a competitor.

[14] This would have introduced a common gun calibre for the British Army and Royal Navy, helping with ammunition logistics, and encouraging joint Army-Navy development of extended-range and precision-guided shells.

[15] The development of this gun for the Royal Navy was stopped due to budget cuts in the Strategic Defence and Security Review 2010.

In 1963 certain NATO nations, including the UK, agreed to a "Ballistics Memorandum of Understanding" for a 155 mm 39 calibre ordnance and a baseline projectile with the shape used for the US M549 rocket-assisted shell.

[citation needed] The vehicle is fitted with an autonomous navigation and gun laying dynamic reference unit (DRU) mounted on the trunnion.