“This could be the biggest IT outage of all time,” broadcaster Iain Dale said live on LBC Radio. Travel passengers from the UK, US, Singapore, New Zealand – and more – are likely to be experiencing travel delays today.

A spokesperson for London Gatwick Airport, as reported by SussexWorld, said: “Early this morning we began experiencing issues with some of our IT systems.

“This is a global Microsoft issue affecting some airlines’ check-in systems, baggage and security, including eGates.”

Reports now circulating across the media, including the BBC, suggest that a security update by the company Crowdstrike, which produces antivirus software, could be the reason behind the global IT meltdown; Crowdstrike have been contacted for comment.

The spokesperson at Gatwick added: “We are using our backup process, but some passengers may experience delays while checking in and passing through security.

“Passengers should still arrive for their normal check-in time, which is typically two hours ahead of the flight time for short-haul, and three hours for long-haul. We apologise for any inconvenience and are working to resolve the issue as quickly as possible.”

Queues at Stansted Airport are growing because of the IT outage, but a London Stansted spokesperson assured: “Flights are operating as normal.”

Check-ins are operating manually at present, but its main operational systems have been unaffected. Meanwhile, some retail payments at the airport have been affected.

London Luton Airport posted to X, formerly Twitter: “We are aware of an ongoing IT issue that is impacting check-in and boarding procedures for some airlines.

“We have additional staff on hand to support and operations are continuing with manual systems. Passengers are advised to check with their airlines for flight updates.”

Under UK law, airlines may have to provide compensation if your flight arrives at its destination more than three hours late.

The Civil Aviation Authority added: “This depends on what caused the delay – if it wasn’t the airline’s fault, don’t expect to receive any compensation.”

Citizens Advice UK said if a flight is delayed for long enough (for two hours or more, depending on the flight distance), the airline has to give you:

• Food and drink
• Access to phone calls and emails
• Accommodation if you’re delayed overnight – and journeys between the airport and the hotel

“The airline might give you vouchers to get these things at the airport. Ask someone who works for the airline if you’re not offered any help,” Citizens Advice stated.

“You’re entitled to get compensation if the flight arrives more than three hours late and it’s the airline’s fault – for example, if they didn’t get enough bookings or there was a technical fault.

“You’re unlikely to get compensation if the delay was because of something outside the airline’s control, like bad weather or a security risk.”

CEO at flight compensation specialists AirAdvisor, Anton Radchenko said: “Know your rights. If an airline cancels a flight for any reason, it has to find you an alternative flight as soon as possible on any airline that has seats available.

“Due to the global IT outage, you might not be able to access your tickets, so prepare secondary evidence like emails from the airline regarding your flight, luggage tags, receipts from the airport you travelled from and scans of passport stamps to use as evidence on the flight(s) you are claiming for.

“Airlines often initially try to offer compensation in the form of vouchers. We suggest to our clients that they refuse vouchers and avoid signing agreements accepting vouchers as a form of compensation, as airlines may later try to use this kind of documentation to reject your claim. Bear in mind that passenger regulations require airlines to pay compensation in cash.

“For flights that are cancelled you are likely to be able to claim between £220 and £520 compensation from your airline for the inconvenience, depending on the distance of your journey.”

If your flights is delayed you could be due:

• Less than 2 hours – £105 to £250
• 2-3 hours – £210 to £250
• Over 3 hours – £210 to £520

“Act quickly, as airlines often have a large backlog for compensations claims, use a flight compensation calculator to establish how much you might be owed,” said Anton Radchenko.

This is a breaking news story with more information to follow as soon as possible with more information.