Experts believe there is 3-23 trillion tonnes of coal buried in the seabed starting from the northeast coast and stretching far out under the North Sea.
Data from seismic tests and boreholes showed that the seabed held up to 20 layers of coal, most of which could be accessed using technology already used to extract oil and gas.
It has long been known that Britain’s coal reserves extended towards the North Sea, but geologist have been unable to determine the extent until now.
The government is planning to extract the first boreholes from the seabed using a rig on the coastline close to Tynemouth, near Newcastle later this year.
The North Sea coal is believed to be the remains of vast swampy forests that covered what is now Europe and North America when the continents were joined together around 310million years ago.