LONDON (AP) -- Britain's transport chief has summoned the head of the country's air traffic control operator to explain the problem that grounded and diverted dozens of flights Wednesday.

More than 150 flights were cancelled across the U.K. as a result of what the National Air Traffic Service, or NATS, described as a "technical issue" at the Swanwick control center that forced it to limit the number of aircraft in the London area. The problem was reported at 4:05 p.m Wednesday and the system was fully operational by 5:10 p.m., NATS said.

Transport Secretary Heidi Alexander will meet with NATS Chief Executive Martin Rolfe on Thursday to "understand what happened and how we can prevent reoccurrence.''

"The transport secretary is summoning in today the chief executive of of NATS to help us get to the bottom of what went wrong yesterday,'' Business Minister Gareth Thomas told Times Radio. "Clearly, an incident happened two years ago and measures were taken then. It looks like those measures weren't enough, but we need to get to the bottom of what exactly happened, and conversations will take place today."

Among those hit was British Airways, which said the problem forced the carrier to reduce the rate of flights from 45 to 32 per hour for more than two hours.

While airlines expressed frustration over flight disruptions, industry experts said it was "unrealistic" to expect an air traffic management system could function without any technical failures.

"There are technical failures in all industries," Graham Lake, a former director general of the air traffic management industry association Canso, told the BBC. "I'm a regular rail user, certainly there are signal failures practically every day, so we accept technical failures. Radio programs go off the air occasionally, technical failures are inevitable. The point is that you have to ... plan the contingency and make sure that the operation remains safe and effective.''

The NATS system has suffered several software-related failures since it opened in 2002.

A glitch in August 2023 resulted in flight plans being processed manually rather than automatically. Hundreds of flights were delayed or canceled at the height of the summer holidays, affecting some 700,000 passengers.