National Air traffic Services Ltd, the main UK supplier of Air Traffic Control Services.
They provide all the en-route Air traffic Control in the UK from 3 area centre, London (Swanwick), Scottish (Prestwick) and Manchester.
They also provide a service to aircraft crossing the North Atantic from the Scottish Centre (only called Shanwick)
They also provide aerodrome and approach services to a large number of UK airports, inclunding Heathrow, Gatwick, Manchester, Birmingham, Stansted, Luton, Cardiff, Glasgow, Edinburgh, Aberdeen, London City, Southampton