Garry Graham, Prospect National Secretary said: “Our members in NATS provide a safety critical public service. We believe any profit should be reinvested in staffing and technology. The UK has some of the busiest and most complex airspace in the world.

“The travelling public will welcome the fact that delays remain at an historic low and that the UK has some of the safest airspace in the world. These achievements are testament to the hard work, professionalism and commitment of our members working in a highly pressurised environment.

“We were given a commitment when NATS was privatised that it would be run on the basis of “not for commercial gain”. Management has lectured employees and unions on the need to reduce staffing levels and costs at the same time as posting record profits and dividends to shareholders. There is real anger among members because they believe that they have more than kept their side of the bargain.”