HMS Trenchant (S91) was a **Trafalgar-class nuclear-powered fleet submarine** of the Royal Navy, the fifth of seven boats in the class, built by Vickers Shipbuilding at Barrow-in-Furness. Launched in November 1986 and commissioned in January 1989, it specialised in hunter-killer roles, including anti-submarine warfare, intelligence gathering, Tomahawk cruise missile launches (notably firing the first Block IV variant in 2007), and Spearfish torpedo operations. Over its 33-year career, Trenchant conducted extended global patrols, participated in Arctic exercises such as surfacing through ice during ICEX 2018, completed the longest Royal Navy SSN patrol in 2013, and served primarily from HMNB Devonport. It was decommissioned on 20 May 2022 in a joint ceremony with HMS Talent at Devonport, attended by The Princess Royal, as part of the transition to the Astute-class submarines, with HMS Audacious as its effective replacement.
