Luton ATC is in its third year of a 10 year deal which saw radar re-locate to West Drayton and all staff transfer onto the NATS pay roll. I understand the ATC staff at the time forced the airport operators to transfer control to NATS once it had been decided to contract out ATC, rather than face certain redundancies proposed by other bidders.
TBI is a British company but they did however, purchase Airports Group International (A US based company which was once part of Lockheed) who had a share in the consortium that runs Luton airport on behalf of Luton Borough Council, therefore TBI are large shareholders within the current consortium having obtained another share of the business from Barclays bank.
Many of the staff have moved onwards and upwards within the NATS career structure since changing employers.