We all live in a Windows submarine...

The British government is defending its decision to implement Microsoft Windows 2000 on some of its Navy fleet.

MPs and security experts have asked Ministry of Defence (MoD) minister Geoff Hoon to explain why the department has chosen to use the operating system on some of its submarines and ships instead of Unix.

The MoD has so far implemented Windows 2000 on its Type 45 Destroyer ship and some Trafalgar type submarines, but denied it has taken any decision to use it on its new nuclear submarine -- the Vanguard.

"It's not like we load everything with Windows and off we go," said a spokesman for the MoD. "There is a lengthy testing period with this. We're satisfied that [Windows 2000] is safe, secure and will perform appropriately. It has gone through independent evaluation against the strictest of criteria."

"The safety of all our nuclear submarines is of paramount importance and we would not introduce a system on board that would jeopardise their safety."

Security experts, including one ex-army professional, contacted the Liberal Democrats when they heard about the government's decision. The Liberal Democrats have written to Hoon's department asking for its reasons for using Windows 2000.

"We are concerned," said Matt Waldman, defence advisor to the Liberal Democrats. "Windows is not known for being a secure system, and we want to know if it's sustainable for the Type 45 Destroyers and Vanguard Destroyers. We want to see evidence why they have not used an alternative system for protection against hackers. We want answers and we want them quickly. Particularly in the context of ever more sophisticated terrorists with more money behind them."

The MoD said it was also implementing 'middleware' to protect its system. But security experts criticised its actions.

"Middleware could be anything -- it could be a firewall or an element of the software, and that's only as secure as it's configured," said director of security for Whitehat UK Jason Hart. "I think it's crazy that a Ministry of Defence spokesman has said that Windows 2000 is being used on a variety of ships. From a risk point of view that's like saying 'Hello world, we're using Windows.'"

Microsoft did not immediately respond to a request for comment.