The UK cannot have a repeat of the travel disruption seen at airports, the foreign secretary has said.

Asked about the flight chaos, Ed Miliband told BBC Breakfast:

First of all, I want to apologise to all of the passengers who have faced disruption.

This is frankly unacceptable. It was a problem at the National Air Traffic Service, but we can’t have this happen again.

The transport secretary, Heidi Alexander, is calling in the head of the National Air Traffic Service this morning to get answers to this. Miliband added:

Frankly, we’ve got to have our airports running smoothly and properly, without those problems, and that is what the transport secretary will be asking for from the head of the National Air Traffic Service.

The boss of National Air Traffic Services, Martin Rolfe, has ruled out a cyber attack as a cause of the flight chaos, and apologised to passengers caught up in the flight chaos caused by a system issue on Tuesday, and said he understands their frustration –- but stressed that safety comes first.

Speaking to BBC radio 4’s Today programme, he said:

I’d like to start, as you might expect, by apologising to everyone who’s been impacted by the issue that we had yesterday.

In terms of the recovery, I absolutely understand the frustration. There is nothing we hate more than delaying people, and not allowing them to get to their destination. It disrupts airports and disrupts airlines. And we absolutely take accountability and responsibility for that. That is our job. But our job is also to make sure that people stay safe. We never do this lightly.

He ruled out a cyber attack.

We will be doing a very, very thorough and full investigation. We have at this point ruled out cyber. We don’t believe it was a cyber attack.

Obviously my focus and that of the team has been on both getting our system operating back up normally, which it is now. But there’s obviously a huge tail to the disruption. And we’ll be working on that through the course of today.

And then obviously our attention will turn to exactly what’s happened, this particular incident. What I will say is I don’t believe we’ve ever seen an incident happen more than once. So this will be something different that we’ve never seen in 50 years of operation.

Rolfe insisted that Nats dealt with the issue as quickly as it could:

We had everybody on site. Everybody was in the right place. We had all the engineers in place. We had our various partners from software industries and so on, all on hand. So this was resolved as quickly as it could be, but within the limits of making sure that it all stayed safe.

In the markets, oil prices are rising towards the $100 a barrel level for the first time since July.

Brent crude has jumped 1.5% to $99.36 a barrel, as escalating attacks across the Middle East are fuelling fears over supply disruptions.

Iranian-backed Houthis in Yemen launched strikes on several Saudi cities while US forces hit several Iranian oil tankers and Iran targeted a US base in Jordan and attacked ships.

Good morning, and welcome to our rolling coverage of business, the financial markets and the world economy.

The boss of the air traffic control provider Nats has been summoned by the UK transport secretary, as flight chaos carried on into a second day after a system issue, with after more than 1,300 flights cancelled to and from UK airports.

National Air Traffic Services provides air traffic control services to 15 UK airports. Its chief executive Martin Rolfe is due to speak to Heidi Alexander, before she addresses MPs in the Commons for the second reading of the Civil Aviation Bill.

Tens of thousands of passengers have been caught up in the chaos, with more cancellations and delays expected as airlines deal with the knock-on effects at airports including Heathrow, Gatwick, Manchester and Stansted.

According to FlightRadar, 246 flights had been cancelled at Heathrow Airport by 6am on Wednesday, while Gatwick passengers faced 33 cancellations.

Rolfe said he “always accept(s) full responsibility” when asked if he was considering his position after the incident.

He told Sky News:

I am the CEO of a piece of critical infrastructure, so it is my job to take responsibility for that.

What I absolutely take responsibility for is keeping people safe and delivering the best service we possibly can on a day like today.

You will understand my focus is entirely about how we actually resolve this issue, get things back to normal, help our airlines, our airport customers and the travelling public.

The “technical issue” at the air traffic control services provider Nats caused Britain’s third major stoppage in just over three years. Nats said on Tuesday evening:

This has been a very complex recovery and has created difficulties for the whole aviation network, from which it will take time to recover.

The breakdown started at about 1pm on Tuesday and affected departing flights at many of Britain’s biggest airports including Heathrow, Gatwick, Manchester and Stansted. By the time Nats said it had fixed its flight processing system almost four hours later, most flights scheduled to depart were yet to take off. The disruption spread to include incoming flights to much of southern England.