But the union, which represents 3,000 staff working within NATS as air traffic controllers, engineers, scientists and specialists, has warned that any operating surplus generated by the public-private partnership needs to be reinvested in the business if these records are to be maintained.

Garry Graham, Prospect National Secretary for Aviation, said: "These achievements in safety, as well as sustaining an historic low in terms of flight delays, are testament to the hard work, commitment and professionalism of our members, working in a pressurised environment and in an industry which has seen an unparalleled growth in demand in recent years.

"It is because the UK has some of the busiest and most complex air space in the world that it is vitally important that investing in safety remains at the heart of everything we do."

Commenting on the news in the report that NATS has posted profits of £80.3 million, Graham said the union was committed to the belief that any operating surplus should be reinvested in the business, both in terms of staff and infrastructure.

"We were given a commitment at the time of privatisation that the operation would be run on a ‘not for profit basis’. As far as we are concerned, staff have more than kept their side of the bargain in terms improving safety and reducing delays despite the increased pressure of air traffic growth."

Prospect is the recognised leading union on air traffic control issues.