Scientists have unveiled plans to create a 21st century nano computer - using an idea first developed by Charles Babbage 200 years ago. Babbage's 'difference engine' was proposed in 1822. Weighing more than 13 tonnes, it was made up of 25,000 individual levers, cogs and other components used to work out calculations. And it worked.

Now scientists writing in the New Journal of Physics have proposed to build a new version of the machine from nanometre-sized components. That means each part would be mere billionths of a metre across. Nano technology is also insusceptible to electromagnetic pulses.

Professor Robert Blick at the University of Wisconsin-Madison is behind the project. He told the BBC that the project could mean that Moore's Law can continue to be upheld.

The Law was proposed in 1965 by Intel co-founder Gordon Moore. It stated that the number of transistors on a microprocessor would double every 24 months - an adage that still holds true today.