Sean Phelan, one of the UK’s prominent internet entrepreneurs, is set to be some £25m ($51m) richer after selling Multimap, his mapping company, to Microsoft.

Microsoft has not disclosed how much it had paid for the privately held business, but bankers estimated that the company, which is expecting £12m in revenues this year, could be worth about £50m. Mr Phelan owned just over 50 per cent of the company.