Some reassurance has come from military minds in the US Defence department in respect of the potential year 2000 computer crash. Weapons systems are said to be on track to be certified as capable of year-2000 operation. Officials noted that, as a matter of standard operation, most weapon systems receive regular maintenance and upgrades. Clocks in many weapons measure time in seconds - from launch to target - and rarely worry what year or month it is, the officials said.

When major defence systems are in the field for tests, commanders are being asked to roll the system clocks forward to 2000 to see what happens.

At one such test last year, the Global Command and Control System crashed, apparently because one piece of software failed, said Mr Anthony Valletta, the acting assistant defence secretary for command, control, communications and intelligence. The system helps control the planning and execution of military operations around the world.