HMS Trenchant was a Trafalgar-class nuclear-powered fleet submarine of the Royal Navy built by Vickers Shipbuilding, Barrow-in-Furness. Trenchant was based at HMNB Devonport. She was the third vessel and the second submarine of the Royal Navy to be named for the characteristic of vigour and incisiveness. Following the Integrated Review of 2020, Trenchant left active service in 2021 and formally decommissioned in May 2022.