A look at Microsoft's Surface tablet
Microsoft has launched its own-brand family of tablets in an attempt to challenge the dominance of Apple's iPad.
Although Microsoft has not disclosed sales figures, it said that pre-orders of the 32GB version of the Surface - which costs £399 - had "temporarily sold out" in the US, Canada, France, Germany and the UK within a day of going on sale.
A £559 64GB version remains on offer.
The BBC's technology correspondent Rory Cellan-Jones tested the device.