A HAMPSHIRE air traffic control provider has been told to improve its contingency planning following claims that staff shortages were delaying flights.

An investigation by the Civil Aviation Authority (CAA) found that Swanwick-based NATS had “too few operational staff” following significant cuts, short-term sickness and a reluctance by controllers to do voluntary overtime.

The investigation followed complaints by Ryanair and Stansted Airport.

Ryanair claimed that more than 100,000 of its passengers in London were disrupted due to flights delayed by NATS’ staffing shortages in the first half of last year.

In June 2016, the Irish airline said that 139 flights to and from the capital were delayed by a total of more than 5,000 minutes because of the issue.

Stansted Airport in Essex also accused NATS of discriminating against airlines using its airport in favour of those at Heathrow.

A statement from airport bosses said: “Stansted was the worst performing airport in the UK for air traffic control-related delays in April 2016.

“In the weekend of July 2 and 3 last year controller shortages meant just ten flights per hour were allowed to land at the airport, down 65 per cent on normal aircraft movements.”

They added that they welcomed the thorough investigation and the report’s recommendation that NATS should identify areas to improve performance and operational resilience at London Stansted.”

However the CAA concluded that NATS had not breached its licence obligations although the regulator said they needed to improve it’s staffing efficiency by better understanding how shortfalls affect airlines and airports.

Richard Moriarty, the CAA’s director of consumers and markets, said: “This is the first time that the CAA has used its investigatory powers under the Transport Act 2000 and highlights the potential seriousness of the complaint raised.

“In this instance our investigation has found no compliance breach, however improvements to operational resilience are key to ensuring service delivery levels are maintained in our increasingly busy airspace.

In response, a NATS spokeswoman said: “The safe air traffic control service that we provide to 2.5 million flights per year is recognised by our customers as one of the best and most resilient anywhere in the world.

“We continually seek to refine our operation particularly in light of the substantial and unforeseen growth of traffic across the south east of the UK since early 2016. Consequently, we are pleased to confirm that we have already taken a number of the actions referred to in the CAA’s report.”

NATS covers the UK and eastern North Atlantic from its centres at Swanwick, Hampshire and Prestwick, Ayrshire. NATS also provides air traffic services at 14 UK airports; at Gibraltar and a number of airport towers in Spain.