Dozens of flights have been cancelled at the UK's busiest airport as the fallout from the weekend's heavy snow continues to cause disruption for passengers.
Heathrow said it was operating three-quarters of its full schedule as airlines dealt with the knock-on effects of Sunday's heavy snowfall, which turned to ice overnight as temperatures plummeted.
Passengers shared images on Twitter of long queues and scores of suitcases lined up on Sunday evening, while others complained of a lack of information from the airport and airlines.
Rim-Sarah Alouane was still waiting to travel, without her luggage, at Heathrow more than 24 hours after her intended flight to Washington DC had been due to take off at 11.25am on Sunday.
The 33-year-old, from Toulouse, said she had then boarded a rebooked flight on Sunday evening but the plane was struck by an electrical fault and the passengers had to disembark.
She said: "It's shameful, I'm drained, I'm exhausted. I've got a migraine but my meds are in my suitcase.
"Both apps, British Airways and Heathrow, were giving conflicting information, then there was an electrical fault with the plane. And the problem was once I got outside the plane, it was absolutely chaotic.
"We had old people crying, some people could not speak English and there was luggage everywhere in the terminal."
Also among them was Beth Kanter, a non-profit and charities consultant from San Francisco, who said the British Airways flight she boarded was cancelled on Sunday after six hours on the tarmac.
She said she was told on the aircraft that the weather was "an act of god" and that the airline could not pay for a hotel as a result.
She said: "(They were) saying they were waiting for de-ice. Then, they cancelled our flight. Then it took me four hours to get through the immigration line. On the plane, the pilot said that we would be able to collect our baggage in baggage reclaim. That was the 'good news'.
"Then, after standing in line and finally making it through immigration, the baggage area was total chaos. There was baggage on the baggage claims but none of the signs indicated what the flights were.
"There was a huge long line - it must have several hundred people in it - stretching from baggage claim number three to the last one where customer service was. There was one person there.
"Then I noticed a man with a BA sweatshirt come out of a back office with a paper with the list of flights and baggage claim numbers - this was after being in baggage claim for hours, trying to figure out what the hell to do."
The consultant, whose luggage "filled with holiday gifts" was lost in the chaos, said she asked for information on her flight which was "not on his list", but eventually received a rebooking for Monday.
"They announced that everyone should go home and come back tomorrow to deal with their bags...people were really pissed off and it was stressful" she added.
A Heathrow spokeswoman said: "Some flights at Heathrow are disrupted today.
"However, the airport remains open and is operating three-quarters of scheduled flights. Before coming to the airport, passengers must check their flight status with their airline. If the status of your flight is cancelled, please do not travel to the airport, keep updated via the airline's website.
"The safety and comfort of our passengers is always our first priority and we are working closely with our airlines to ensure affected passengers are looked after. We apologise to those whose travel has been impacted and regret the inconveniences that have been caused."