If Microsoft made cars, the joke goes, they would crash twice a day, need regular upgrades and have to be replaced every time the lines on the roads were repainted.

But Microsoft does not regard car software as a subject for jest. Last week the software giant demonstrated the first production cars, Fiats and Alfa Romeos, running the full version of Windows Mobile for Automotive at the Geneva motor show. On Thursday it will show off a Volkswagen concept car offering full internet access at the CeBIT technology exhibition in Hanover.