Overseas, WiFi and 3G versions of Opal will be sold by several carriers and HP in the UK, Germany, and France, while a WiFi only version will be in Italy and Spain, only through HP.

FORBES: HP's Tablet Leak on Partners, Marketing

The Air Survey is part of the OPAL project, which is funded by the Big Lottery Fund.

BBC: York & North Yorkshire - Can you help identify lichen?