The organisers of the Paralympic Games have been accused of discriminating against the disabled by making wheelchair users book tickets for events via business rate phone lines.
Those trying to book wheelchair tickets or check their availability can only do so by calling an 0844 number costing up to 41p a minute, while able-bodied people can buy their tickets online from organiser Locog without incurring extra costs.
The arrangements have caused outrage among some disabled people who say they have been kept on hold for long periods of time running up large bills before being told there are no seats available.
Many have complained about the situation on blogs and social networks with a Facebook campaign group called "Stop the Olympics from discriminating against wheelchair users!" attracting close to 700 members.
The London 2012 website has a specific section for disabled people wanting to buy tickets to the Paralympics, which start on Wednesday. It says: "If you require a wheelchair space, you will be able to purchase one, subject to availability, by calling 0844 847 2012."
According to communications regulator Ofcom, 0844 calls are charged between 1p and 13p per minute for landline customers. Calls from mobile phones are typically charged between 15p and 41p per minute, depending on the network provider.
Nicola Carlin said she called the ticket hotline more than 20 times on her Orange mobile phone, which charges 40p per minute, and on some occasions spent up to half an hour on hold.
The children's nurse, whose disabled five-year-old Matthew suffers from cerebral palsy and is confined to a wheelchair, told the Daily Mail: "I can't understand why the organisers made it so difficult for people like us to get tickets. There's no mention on the phone line of how much it costs, and people like me who have been desperate to get tickets would have held on for ages."
The 31-year-old, from Stockport, Greater Manchester, eventually got through, but added: "The Paralympics, of all occasions, should be making it easier for disabled people to enjoy sport, not putting up barriers such as this."
An online petition has been set up by Beth Davis-Hofbauer calling for the rules to be changed and has attracted nearly 40,000 signatures.
Baroness Grey-Thompson, speaking at St Paul's Cathedral before a service to mark the opening of the Paralympic Games, said: "I know there were a few issues.
"The reason Locog directed people who needed specialist assistance to a phone line was so they had a person to talk to, that they could ask and get the tickets that they needed.
"I think the intentions were good. I think what has just blown everyone away is the interest in tickets and the fact that so many of the wheelchairs tickets went."
Baroness Grey-Thompson said she was aware of varying costs for wheelchair users trying to book tickets by phone.
She added: "Basically the figures I've heard are between 5p and 35p a minute.
"Obviously 5p is kind of ok, 35p is not."