A second technical problem affecting the UK's air traffic control system within two weeks caused widespread flight disruption across Scotland, Northern Ireland and northern England. Airlines criticised Nats, warning that repeated failures had damaged confidence in the resilience of the national system and calling for urgent reform and greater accountability.

Nats said a connectivity issue at Prestwick was responsible and was unrelated to the software defect at Swanwick that caused about 2,000 cancellations earlier in September. At least 200 flights were cancelled or did not operate, including 47 easyJet and 11 British Airways departures, while Ryanair said 140 of its flights and 25,000 passengers were affected. The Civil Aviation Authority said passengers were unlikely to qualify for compensation because the incident would probably count as an extraordinary circumstance, although airlines should still assist affected travellers.