For a building under 15m in height you're permitted a maximum of two antennas (which includes conventional TV aerials, radio aerials and satellite dishes) on your property, subject to certain limitations upon their size. Thereafter you require planning permission.
http://www.planningpo...mmonprojects/antenna/
(It would be interesting to see what would happen if anyone tries to enforce the covenants on the houses on the estate where I live. All external antennas are prohibited which means that, since nobody can get a signal with an indoor aerial and there's no cable service, nobody is allowed any means to access any TV signals).
Chris