Flight delays at UK airports are expected to continue into tonight after air traffic control took 'longer than it hoped' to fix an issue with its 'flight processing system'. More than 1,000 departures and arrivals into British airports were cancelled today, with thousands of passengers left stranded.A dozen of the country's major airports - including Heathrow, Gatwick, Manchester and Birmingham - are affected with scores of planes grounded on runways. More than 60 per cent of all flights at London City were cancelled, while figures showed that 91 per cent had been delayed in Manchester. Aberdeen, Edinburgh, Glasgow, Nottingham and Bristol Airports have also announced they are impacted.Pictures taken at Stansted Airport in Essex showed hordes of flyers waiting for updates on delayed trips and refunds in the terminal. And across the capital in Heathrow - where arrivals are suspended until tomorrow - holidaymakers were seen crammed together near ticket desks as queues spilled out of the airport's terminals. Passengers flying out of the west London airport to New York this afternoon were meanwhile left stranded on the runway for as long as nine hours. Thousands of holidaymakers, including at Heathrow and Gatwick, are facing hours of delays, with disruption expected to last into tonight Hordes of flyers are seen waiting for updates on delays at Stansted Airport in Essex Other stranded jetsetters were pictured frantically checking their phones at Stansted At Heathrow, passengers were seen crammed together near ticket desks as queues spilled out of the airport's terminals Parked planes at Heathrow Terminal 5 in London on Tuesday as departing flights were cancelled or delayed An update board at Heathrow showed how dozens of flights had been delayed and cancelledElsewhere, Arsenal's flight from the capital for a Champions League match in Naples was delayed, forcing the club to cancel a press conference in the Italian city tonight. It came after National Air Traffic Services (NATS) suffered an issue with its 'flight processing system', which has only now been resolved. NATS, however, warned that delays are expected to continue as it tries to 'clear a backlog of flights'. 'Recovery from today's system issue has taken longer than we had hoped,' it said.'Our system issue is now resolved, we are operating normally and working as hard as possible to clear the backlog of flights.'We are truly sorry for the ongoing flight disruption. We know this is hugely frustrating and apologise unreservedly. Passengers should continue to check with their airline.'A spokesperson has since urged passengers to check with their airline on the status of their flights tonight and tomorrow. 'Work is continuing to assist airlines and airports recover from today's disruption. This has been a very complex recovery and has created difficulties for the whole aviation network, from which it will take time to recover,' they said. 'We apologise again for the disruption caused. Passengers should check with their airline on the status of their flight tonight or tomorrow.'The organisation, which provides air traffic control services to 15 UK airports, gave no details as to the cause of the problem. But a spokesperson told the Daily Mail there is currently no indication the issue is due to a hack or other cyber incident. An air tracker found 352 flights to and from Heathrow were delayed out of its daily average of about 1,300.Meanwhile 281 Gatwick flights were delayed out of its 850 daily average. This was 249 out of 650 for Manchester, and 101 out of 300 for Birmingham.Ryanair said more than 65,000 of its passengers have been affected and called for 'overpaid failure' NATS CEO Martin Rolfe to be replaced.COO Neal McMahon said: 'The UK Government, the CAA and the NATS Board must stop making excuses for repeated NATS failures and appoint a new leader capable of running the UK ATC system without repeated failures. Its time for overpaid failure Martin Rolfe to go.' Wizzair later joined Ryanair in its criticism of NATS, saying it was 'extremely disappointed' that another failure caused significant travel disruption. The airline continued: 'A critical national infrastructure provider should not repeatedly bring the aviation system to a standstill. NATS is simply not fit for purpose in its current form.'And Shadow Transport Minister Greg Smith tonight took aim at the service, which is 49 per cent Government-owned.He said: 'Yet again passengers are stuck on the tarmac wondering why Britain cannot keep its own skies open. The Government and NATS must explain what has happened and how they will make sure resilience is improved.' NATS CEO Rolfe later responded to calls for him to resign during an appearance on Sky News, describing the incident as 'unfortunate'.He added: 'I always accept full responsibility. 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.'Rolfe said the service does 'not yet have an idea' of what caused the disruption. In its latest update, FlightRadar24 said that 218 easyJet flights, 132 from BA, 42 Ryanair, 37 KLM and 22 Eurowings flights had been cancelled. In an update tonight, Manchester Airport said: 'Following today's NATS air traffic control issue, flight disruption is expected to continue for the rest of the day while airlines recover their schedules.' Heathrow meanwhile announced that all arrivals into the airport had been suspended on Tuesday for passengers' 'safety'. Departures have however since resumed. Passengers are being urged to check in as usual but check with their individual airlines for updates. Some inbound flights from continental Europe are being held on the ground and disruption has also been reported in Ireland. Flight radar data shows planes stuck at airports across London due to an air traffic control failure A dozen airports across the UK reported minor to major disruptions as a result of the issue. File photo of planes on the ground at Gatwick Pictures from Heathrow showed a huge crowd of holidaymakers had been left stranded in the terminal A man and a woman are seen trying to figure out an alternative route out of Heathrow tonightOne passenger who was travelling from Dublin to Malta told the Daily Mail their flight had been affected by an 'issue in London'. They said: 'Our Aer Lingus flight to Malta was due to depart at 2.20pm and we've had zero information from the Aer Lingus. 'They just keep saying an update will be provided in 15 mins - there's an issue in London but no information regarding departure time or how long we will be delayed.' Pictures showed queues for Ryanair's ticket desk at Dublin Airport stretching for almost the length of the terminal. Other flyers have shared their experiences of being stuck at airports on social media. One person posted on X: 'We are currently sat on Alicante tarmac going to Manchester and this is affecting us. Not just London!' 'Luton airport too! We're stranded on the actual plane,' another added. Passengers are being advised to travel to the airport for their scheduled time and to check in with their airline. Today's disruption comes after NATS suffered another major outage in August 2023 that affected more than 700,000 passengers. It happened after the body suffered a technical glitch while processing a flight plan. The disruption - which occurred on one of the busiest travel days of the year - caused airlines to lose around £100million in refunds, bookings, hotel rooms and refreshments. More than 150 flights across Britain were also cancelled last year after a malfunction left air traffic controllers at the control centre in Swanwick, Hampshire, with only a patchy view of the airspace.In a post on X, Transport Secretary Heidi Alexander said she was aware of the issue impacting flights and that engineers were 'fixing it as we speak'.She said: 'I'm aware of a technical issue impacting flights at airports including Heathrow and Gatwick. Technicians have identified the issue and are fixing it as we speak.'I know this will be frustrating for passengers and I'm sorry. Please check with your airline for latest advice.'A spokesman for Heathrow Airport added: 'The air traffic control service is experiencing a technical issue which is impacting departing flights at UK airports. Arriving flights are not currently impacted. 'We are supporting our local NATS team in their efforts to resolve the issue as quickly as possible. We will provide updated information when we have it. 'We apologise to those disrupted and advise passengers to check with their airline for latest flight information.'Jersey Airport said it was also affected by a technical issue with air traffic control.In a statement the Channel Islands airport said: 'UK air traffic control is currently experiencing issues which is impacting flights across the UK including services between Jersey and UK.'Passengers are advised to check the latest flight information directly with their airline.'A spokesman for Gatwick added: 'We are aware of a NATS technical issue that is currently affecting a number of UK airports, including London Gatwick.'Passengers are advised to check with their airlines for more information regarding their flights.'Airlines have also warned passengers of delays, but stressed the situation is not under their control.EasyJet said some of its flights are 'unable to operate' following the technical issue. It is the latest issue to affect passengers flying out of the UK, with flights at Gatwick brought to a standstill last week after a plane became stuck on the runway. The plane was surrounded by several fire engines and the runway was closed for around 50 minutes.Meanwhile, in July passengers at Gatwick were left without running water due to an issue with the supply. Flyers were unable to flush toilets, wash their hands or refill water bottles for hours during the outage. Heathrow has also been affected by two grass fires this summer, which have caused delays to flights. One flight from San Francisco was diverted away from Heathrow towards Manchester and another from San Diego landed in Birmingham due to a blaze on September 5.In early August, flights were disrupted after a grass fire ignited near Heathrow's southern runway.One hectare of grassland was destroyed by the fire as 18 inbound flights were diverted to other airports.Are YOU affected? Email: elizabeth.haigh@dailymail.co.uk