Mark Harper, UK Transport Secretary has said that he apologises for the disruption caused on Monday by a breakdown in the air traffic control system, but that the outage was not caused by a security breach.

Although the ‘technical issue’ was fixed in a matter of hours, disruption will continue through the week as planes and crews are in the wrong place. Monday was a Bank Holiday in the UK and a higher number than average were traveling when the system went down.

While he wouldn’t be drawn on what the cause of the outage was, when asked by BBC radio if a cyber hack could be ruled out, Harper replied: “Those who look into these things were clear that it wasn’t a cyber-attack. They will continue to look at these things, but the timing was not at all helpful”.

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When asked why the UK hasn’t implemented a parallel server, as is apparently used in other critical infrastructure, the Minister said: “The [manual] system was very resilient as it kept flights flying but it doesn’t have the same capacity as the system when it is operating normally. So there is a failsafe system that keeps flights going, but it does mean that a significant amount are cancelled”.

It has been a significant week for travel disruption in the UK. Apart from the issues caused with air traffic control, a number of strikes have been announced by the RMT trade union on the rail network. In addition, London’s Mayor, Sadiq Khan has pressed ahead with expanding a controversial low-emission scheme which will see older vehicles effectively banned from entering a zone coving most of Greater London and parts of surrounding counties.