Air chaos: Vince Cable accuses Nats of poor investment
The UK's national air traffic service (Nats) has been accused by Vince Cable of "skimping on large scale investment" after an IT glitch led to widespread disruption across UK airports.
The business secretary said Nats had been "penny wise and pound foolish".
He said it was running "ancient computer systems, which then crash". "We have to maintain a high level of capital investment," he added.
Nats said it would be spending £575m over the next five years on systems.
Mr Cable told BBC's The Andrew Marr Show that Nats, under financial pressure, had decided to "forego capital investment" for many years.
He said: "We have to maintain a high level of capital investment."
Faulty line of code
His comments follow Friday's disruption to UK flights caused by a computer malfunction at Nats's Swanwick centre, which typically handles about 5,000 flights every 24 hours.
The problems caused dozens of arrivals and departure flights at airports across southern England, and as far north as Aberdeen and Edinburgh, to be delayed or cancelled, and almost 40 were cancelled at Heathrow.
The disruption affected thousands of passengers.
The problem was caused by a single faulty line of code in one computer system, Nats chief executive Richard Deakin confirmed.
He told the BBC that the software problem was "buried" among millions of lines of computer code.
"The challenge is that we have around 50 different systems at Swanwick and around four million lines of code. This particular glitch was buried in one of those four million lines of code.
"We haven't seen that particular issue before," he added.
Labour MP Paul Flynn has called for Mr Deakin to be docked bonuses in his salary because of the disruption.
Mr Flynn, who sits on the public administration committee, told the Sunday Times: "I hope after the chaos, which was dreadful, though a rare event, he will have his bonus stripped from him."
It has emerged that Mr Deakin had his pay package increase by more than 45% this year, to more than £1m, due to the maturing of an incentive scheme.
Transport Secretary Patrick McLoughlin is likely to face questions from MPs on the issue when he appears before the Transport Select Committee on Monday.
On Friday, he said the situation was "unacceptable" and asked for a full explanation from Nats about what had gone wrong and what it would do to prevent such an incident happening again.
Labour has called for ministers to "get a grip" and the chairwoman of the transport select committee, Louise Ellman, said it was "vital that we establish what happened".
It has also emerged that the Civil Aviation Authority (CAA) had previously criticised Nats in a report into a telephone failure which grounded flights in December 2013.
The CAA's warning came after Nats completed a report into the problem, again at the Swanwick control room, which resulted in 300 cancelled flights.
The CAA responded that the service's "themes on avoiding a recurrence" were a "good first step but lack detail and clarity".
A spokesman for Nats said it subsequently provided a further more extensive and detailed report, which satisfied the CAA there were no safety issues.