Gatwick Airport has apologised to a disabled passenger who was left on a plane for more than an hour and a half after it had landed.
Victoria Brignell, who is quadriplegic, said she was initially told it would take 50 minutes to help her from the aircraft.
Her treatment has drawn criticism from former Paralympian Baroness Tanni Grey-Thompson.
Gatwick Airport described Ms Brignell's treatment as "unacceptable".
Ms Brignell said: "I booked the help three months in advance, it wasn't as if I just turned up, they knew I was coming, and I reminded them two weeks ago, and still I didn't get the service that I should expect to have."
Her friend Sonia Sodha tweeted a picture of Ms Brignell on the plane.
Ms Brignell said: "I can't use my arms or legs. To get off a plane I need two people to lift me from the airplane seat into an aisle chair, which is a specially-designed narrow wheelchair to push me along the aisle off the plane, and lift me into my wheelchair waiting outside.
"My wheelchair arrived promptly, but the people who were supposed to help me get off the plane didn't turn up - they were busy elsewhere."
She said British Airways staff were "fantastic", very apologetic and brought drinks while she waited for Gatwick Airport staff to arrive.
'So many horror stories'
But she said she was left unable to use the toilet and her carers could not go off duty, because of the delay.
Other passengers hoping to board the plane for a different flight were also delayed.
Ms Brignell said: "I have been very nervous about travelling by plane because I had heard so many horror stories about people's chairs going missing."
She said this was her second time flying abroad and the fourth flight she had taken.
Ms Brignell said British Airways staff got her off the plane and she received an apology form Gatwick via Twitter, but she plans to submit an official complaint.
She said: "I just feel in 2022 people shouldn't be stuck on a plane for that long.
"UK airports need to get their act together and plan their staffing appropriately."
Baroness Grey-Thompson said she took direct action when she suffered a recent similar experience.
She said: "I was flying to Berlin, the plane was two and a half hours late, but after waiting just over half an hour on board they couldn't give me any clear indication of when the assistance was going to come.
"My chair was at the gate, so I decided to get on the floor and pull myself off the plane."
BBC security correspondent Frank Gardner, who uses a wheelchair, said such situations were becoming "depressingly familiar".
"The airports seem to be slipping back. The level of investment and effort that goes into making money at these airports isn't matched by the effort and money that needs to go into getting disabled passengers off the plane at the same time as everybody else."
Gatwick said it would launch an investigation into why Ms Brignell was left on the plane for so long.
A spokesman for the airport said: "The treatment received at Gatwick Airport was unacceptable and I would like to offer our sincere apologies to Victoria.
"This incident has been escalated and Gatwick and Wilson James, our assistance provider, are investigating how this happened as a matter of urgency."
A spokesman for Wilson James said: "We are deeply disappointed to have delivered a poor service on this occasion.
"While the aviation sector in particular is struggling with well-documented pressures, Ms Brignell's experience is unacceptable and falls far below our values and aims."