Energy firms taking part in a North Sea boom for offshore wind farms will have to watch out for remains of Stone Age villages submerged for thousands of years, an expert said on Tuesday.

A region dubbed "Doggerland" connected Britain to mainland Europe across what is now the southern North Sea until about 8,000 years ago, when seas rose after the last Ice Age.

It is now the site of a planned vast expansion of offshore wind power by 2020 to help combat climate change.