The malfunction was first noticed at noon yesterday, and was only fully corrected during the early hours of this morning.

According to airport operator ANA, a total of 64 flights were cancelled, a further 11 diverted to other airports, while 322 suffered delays. Many were allowed to depart after midnight, overriding the limitations of a law limiting noise over the capital.

It is estimated that 50,000 air passengers were affected by this unprecedented problem at Portugal’s largest airport.