Patrick Bossert's 1981 best-selling guide was seen as a godsend to a generation of parents and children baffled by the toy.

One in 500 chips could be affected by Y2K

Now, Mr Bossert is a 30-year-old father of two and technical director of WSP Business Technology. His latest challenge is the so-called Y2K bug that computer experts fear could lead to global computer meltdown.

Systems programmed with two-digit dates may crash if they fail to recognise the year 2000 on New Year's Day.

The Rubik's cube genius and his team have developed a device called the Delta-T that claims to be able to detect whether chips embedded inside electronic equipment will fail when 1999 becomes 2000.

"We have been working on the millennium bug since 1995, and thanks to the Delta-T probe we have confirmed that the work we have done on equipment with embedded chips has been spot on," he told the Times newspaper.

He said that up to one in 500 chips could cease functioning on 31 December, preventing the systems they control from operating.

Among the companies trying out the device are Sainsbury, the supermarket chain, and British Aerospace.

Listening device

The Delta-T probe consists of a lap-top computer linked to an analysis box attached with clips to the back of the chip.

Cables connect the Delta-T probe to embedded chips

The device "listens" to the chip operating and the analysis box is able to establish whether the chip processes the date and time.

If it does, the lap-top computer records the lines of computer code in the chip responsible for that function and sends them off by e-mail for analysis. This shows whether or not the chip is likely to fail.

"Only a very small percentage fail critically. One in 100 might develop faults, but these might not be critical - a fire system might log alarms in the wrong order, for example," said Mr Bossert.

"But one in 500 might fail in a way that would prevent the equipment working at all."