...the Weald Basin left out several factors that could push the oil figure up to closer to 20 billion barrels of resource and also include 200 TCF of gas....
http://www.nohotair.co.uk/index.php/shale-gas-2014/216-shale-oil/3167-what-in-the-world-is-under-the-uk-s-weald-basinToday