Milk
Udderly delicious
The crown own all mineral rights on land no matter If they own it or not, oil , gas ect , it gets taken out on licence from them, the owner would get compo but couldnt stop them taking it, you will see it in action soon in the fracking debate
Actually there was an opportunity for landowners (of which the Crown are one of the largest) to register their "rights" to minerals a few years ago. But your point about fracking is very valid:
http://www.telegraph.co.uk/news/politics/10245697/Church-of-England-in-fracking-land-grab.html