You'll find this information in Pooleys/Bootlang guides....for example (from an old Pooleys):
Heathrow 'may be used for non-scheduled commercial and executive aircraft subject to special conditions listed on p341. Light single and twin engined aircraft will not be permitted to use this airport'. London City won't permit 'helis, SE aircraft and fights for recreation'.
Manchester - 'use by GA and business aviation subject to prior permission'. I was ok'd to take a twin in recently but at £160+ landing/mandatory handling charges for a non peak arrival/departure and no parking!
You can check the rest yourself.
As hobbit said, the owner/operator (in the case of the large fields) will determine the who will be given permission and how much they will be charged for it. I believe local flying schools tend to be exempt the handling charges which means training can still take place at the larger fields.
I suspect landing outside of operating hours without permission would also be trespass and with permission just expensive without the jail sentence!
W