Frustrated travellers have taken to Twitter to express their fury, frustration and bemusement at the "catastrophic" British Airways computer system failure that has caused widespread delays — grounding flights from London's Heathrow and Gatwick airports.

A tweet by British Airways confirmed the problem on Saturday (May 27): "We apologise for the current IT systems outage. We are working to resolve the problem as quickly as possible."

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But this did little to appease thousands of would-be passengers set to travel over the bank holiday.

Only pic I've got - we are now back in terminal - capt says it's looking like a cyber attack across all BA system- indefinite delay pic.twitter.com/LGa6sCG9Ep

— Phil Davies (@travjournalist) May 27, 2017

The whiteboard is out in terminal 5 #britishairways @BBCNews pic.twitter.com/JCuXlNxn3N

— Martin Patience (@martinpatience) May 27, 2017

Haven't seen any BA planes or otherwise take off in a while. I think that 1 hour 'delay' is just a little bit far fetched @British_Airways

— bex.✨ (@rebekki) May 27, 2017

Not a word from BA customer service .... do they take first class customers for granted #britishairways only time will tell

— Gautam Singhania (@SinghaniaGautam) May 23, 2017

Flying with @British_Airways from @HeathrowAirport ? Don't bother #britishairways pic.twitter.com/2czOBpaL43

— Chris Ship (@chrisshipitv) May 27, 2017

#BA sort it out.. ruining people's holidays!

— Ali Khan (@aliwycombe) May 27, 2017

As airports struggle to communicate amid the confusion, travellers reported that only passengers within 90 minutes of their departure time will be allowed on to the departures floor at Heathrow.

No one allowed on departures floor until 1.5 hours before flight. #heathrow #britishairways pic.twitter.com/rgmHjFLZ2x

— Heather (@HI_Elam) May 27, 2017

@BBCBreaking #britishairways 4 hours at check in only to miss security time and so flight leaves without us and we are told to go home. 1/2

— Jo (@Jo_Josson) May 27, 2017

At this moment my biggest concern is the kilometric queue: any hance #BA will increase support rechecking passengers? https://t.co/gIPsI6F8zH

— A. Alberca (@arubeeka) May 27, 2017

This is becoming a joke @British_Airways! The media are saying flights are cancelled, do we just sit in the departures? Bit more info?

— Gary Tumelty (@gazza_81) May 27, 2017

The incident means passengers are stuck on aircraft waiting to travel, and claim to have been forced to pay for refreshments.

It's absolutely disgusting. We have been left with No info. 22hrs later and we have No idea what's happening. I have 2 small kids 1 with ASD

— Natalie Pinder (@NataliePinder2) May 26, 2017

Stuck on the tarmac at #Heathrow on #britishairways flight. This is ... interesting.

— Kasey Byrne (@kaseybyrne) May 27, 2017

Stuck inline waiting for BA to give us a docking station! Hopefully they'll arrange another flight for us to America! 🇺🇸 #britishairways pic.twitter.com/FO06myFE64

— Jessica Kelly (@Jessica234K) May 27, 2017

Stuck on flight BA0367 for over 1hour as BA Systems are down & having to pay for refreshments...#britishairways @British_Airways @BBCNews

— Alma Saffari (@MissSaffari) May 27, 2017

Heads up, @British_Airways... someone is crafting a STRONGLY WORDED letter about our flight delay. pic.twitter.com/j5uhRXhzEG

— Lazy Travelers (@lazytravelers) May 27, 2017

Disgusting to know that you are SELLING refreshments to passengers stuck inside planes instead of offering a cup of tea as a courtesy.

— Dani (@danimadu) May 27, 2017

This has also affected travellers abroad looking to travel on British Airways flights.

"Enjoy your flight, should there be one!" - currently there isn't one, so I'm stuck in the Vienna lounge until...? #britishairways pic.twitter.com/UgaXmKduf3

— Daniel Pashley (@eurodan) May 27, 2017

Just in ref #BritishAirways : It would appear all BA flights from #schiphol are also halted.

— DutchFlyBird (@DutchFlyBird) May 27, 2017

In the afternoon an announcement at Heathrow Terminal 5 urged passengers to leave the terminal.

Announcement in LHR T5 that the phones and booking systems are down and Passengers should leave the terminal #BA

— Joe Lynam BBC (@BBC_Joe_Lynam) May 27, 2017