Airline Group has warned the government it must alter plans to privatise the National Air Traffic Control Service (NATS).

Composed of seven leading UK airlines - British Airways, Virgin Atlantic Airways, BMI, easyJet, Thomson Airways, Thomas Cook Airlines and Monarch Airlines – the group bought a stake in NATS during its part-privatisation in 2001.

Airline Group has warned it will consider selling its 42 per cent stake if the government carries out plans to sell its holding.

In a letter to Hammond, Airline Group chairman Peter Read warned: “It would be highly damaging if we were on the sidelines while others, notably France, Germany and Spain, decided the future of the air traffic control industry.”

“There is a real risk such an outcome would occur if the UK were the only country without a government shareholding in its national air traffic control.”

The airline fear the UK would lose a voice in discussions on a single air traffic system for Europe if the government retains no stake in NATS.

Any move to completely privatise the service would therefore be “highly damaging”.

The letter – which was seen by the Observer paper -: “The absence of a government stake would make it difficult to justify continued airline participation in the ownership of Nats.”

The group proposes the government retain at least a 25% stake in the system.

The government is due to announce its plans for privatising Nats in the Budget on March 23rd.