To ask the Secretary of State for Defence if he will list the S and T class submarines which (a) have completed, (b) are undergoing and (c) will in future undergo major upgrades together with the (i) completion and (ii) due completion dates in each case. [98241]

Upgrades to S and T class submarines are generally undertaken during docking periods of maintenance lasting six months or during major refit and refuel periods lasting three years. These are known as Upkeep Periods. All S and T Class submarines will undergo a number of Upkeep Periods throughout their lives, and those whose last Upkeep Period included an upgrade, and which are not currently undergoing an Upkeep Period are:

Submarine	Completion date1
HMS Splendid	Spring 1998
HMS Superb	Summer 1998
HMS Tireless	Summer 1999
HMS Triumph	Winter 1999
HMS Trafalgar	Summer 2000
HMS Turbulent	Spring 2002
HMS Sovereign	Autumn 2002
HMS Torbay	Winter 2002
1Dates shown are when the submarine rejoined the fleet.

Submarines currently undergoing an Upkeep Period and upgrade are HMS Sceptre and HMS Spartan, both of which are due to rejoin the fleet by summer 2003 and HMS Trenchant, which is due to rejoin the fleet by autumn 2003.The next planned refit and upgrade is that of HMS Talent which is expected to commence in spring 2003 and take approximately three years to complete including post refit trials and training. Details of Upkeep Periods beyond 2003 are classified, and I am withholding this information in accordance with Exemption 1 of the Code of Practice on Access to Government Information, which relates to defence, security and international relations.