One of the last vessels to be built for the Royal Navy at Vosper Thornycroft's (VT) Woolston shipyard in Southampton is to be named and launched tomorrow.

HMS Severn is the second of three River Class offshore patrol vessels to be built by the VT group under a unique contract with the Ministry of Defence.

The £60m cost of the ships is being funded by VT and they will be chartered to the Royal Navy for an initial period of five years. At the end of the charter the Ministry of Defence will have the option to extend the deal, hand the ships back or purchase them outright.

VT is set to move shipbuilding production to new facilities at Portsmouth as part of a major shake-up of its operations following the clinching of a major contract to help build the new Type 45 destroyer.

During the five-year charter VT will also take on full support responsibility to ensure the 80-metre ships fulfill their operational capability.

The new craft will replace five smaller Island Class ships, which will be disposed of by VT as the new vessels enter service.

HMS Severn is fitted with state-of-the-art machinery control systems supplied by VT together with the latest navigation and communication equipment.

One of the major assets of the ship is a large working deck which can accommodate up to seven containers, enabling the ship to carry elements such as additional stores, workshops, mine counter-measure support equipment, a diving recompression chamber or medical facilities.

HMS Severn is to be launched by Mrs Felicity Guild, wife of Rear Admiral Nigel Guild, Controller of the Navy.