A woman who will miss a wedding because her flight was cancelled by an air traffic control failure said what happened was "disgraceful".
Monica Clare, 68, from Brentford, west London, was onboard an Aer Lingus plane preparing to take off from Heathrow for Shannon, Ireland, on Thursday afternoon when the problem began.
She said the plane remained on the tarmac for about three hours before the captain announced his "shift was going to finish" so the passengers would need to return to the terminal.
Ms Clare said the situation inside Heathrow was "bedlam", with "suitcases everywhere".
The retired maintenance manager returned home after being told Aer Lingus had no available seats on flights which would enable her to attend her friend's wedding in Limerick on Friday.
She said other routes, such as travelling to a port and taking a ferry, were impractical and too expensive after already paying out for flights.
She is now trying to obtain refunds for car hire and hotel bookings.
Ms Clare said: "I'm absolutely numb. I'm so upset. I'm heartbroken.
"It's disgraceful. I think it's absolutely unbelievable in this day and age that something that went down for 20 minutes has caused havoc like that all over the country.
"I'm so upset, I'm so angry.
"I've spoke to my friend who's getting married. They're devastated.
"We can't now go to the wedding. I was so excited, and it's all gone."
Nats (National Air Traffic Services) said a radar-related problem affected flights in England and Wales for about 20 minutes on Thursday.
This caused the cancellation of more than 150 flights, with many others delayed or diverted.
