Flight passengers will be affected by UK air traffic control failures for days, the transport secretary has warned as he urged airlines to step up and fulfil their responsibilities to passengers. Speaking on BBC Radio 4’s Today programme, Mark Harper said National Air Traffic Services (Nats), which provides the air traffic control systems in the UK, had apologised for the disruption, adding: “I’d like to add my apology to that.” Holidaymakers were hit by the delays on bank holiday Monday after a UK air traffic control technical failure meant flight plans had to be input manually by controllers. By Monday afternoon, 232 flights departing from UK airports had been cancelled as well as 271 arriving flights, according to the aviation analytics company Cirium. On Tuesday, Harper ruled out a cyber-attack. He said: “First of all, I want reiterate what Nats said yesterday, they apologised for the disruption, I’d like to add my apology to that, I’ve been in a similar position when flights are cancelled. It’s incredibly disruptive so I do understand that.” “Airlines have a responsibility either to get people back on a flight to get them home or to pay for them to be accommodated and to sort out accommodation of them, and for food or drink as well. If they don’t do it people can pay for reasonable costs themselves and claim back from their airlines,” he added. “There was a technical issue with the flight planning system that will be looked at in detail. When there is a significant issue like this the CAA [Civil Aviation Authority] has to do a report on an incident of this magnitude and report back to me. “I don’t wish at this point to rush to judgment they had to go to a manual system they have as a failsafe. Their primary responsibility is to make sure people fly safely so they had to reduce the capacity of the system.” Asked if this could have been the outcome of a cyber-attack, Harper said: “Those people who look at these things have looked at it and are clear it was not a cyber-attack. They will continue looking at the systems. But you’re right, the timing was not at all helpful at all for people. The system is very busy anyway but particularly on this bank holiday at the end of the holiday period. “I accept it has disrupted thousands of people. Lots of flights were cancelled yesterday because of the imperative to keep the system working safely and it is going to take some days to get completely everybody back to where they should be.” Harper said he did not accept that the wider UK transport infrastructure could not be relied on. “On 99.9% of occasions, the air traffic system works perfectly well millions of people fly into the UK without incident, clearly it was a big problem I’m not minimising it these things do not happen frequently.” Major UK airlines including Tui and BA warned of “significant delays” for passengers amid changes to schedules. Passengers are being urged by airlines to check before they leave for the airport as their flight times may have changed. Heathrow airport tweeted on Monday night: “We apologise for any inconvenience as a result of the Nats technical issues today. The issue has been resolved however schedules remain significantly disrupted. If you are travelling on 29th August, please ensure you contact your airline before travelling to the airport.”Gatwick said it planned to operate a normal schedule on Tuesday, but advised passengers to check the status of their flight before travelling to the airport.