David Allen said he had banked with RBS from the age of 10
A bank has lost its appeal against a landmark ruling that it failed to cater for the needs of a disabled teenager.
David Allen, 18, who has muscular dystrophy, took action after Royal Bank of Scotland failed to put in wheelchair access at a Sheffield branch.
In January the bank was ordered to pay damages and install a platform lift.
Judges at the Court of Appeal dismissed the bank's appeal against the ruling and ordered it to carry out the necessary access work.
The branch concerned is a 19th century listed building in Church Street, where access to all entrances is by flights of stone steps.
The estimated cost for installing the platform lift is £200,000.
The original ruling at Sheffield County Court was the first of its kind and set a legal precedent that could have implications for other service providers, legal experts said afterwards.
The bank told the Court of Appeal it had complied with the Disability Rights Commission's Code of Practice and it had arranged access to three other branches.
Dismissing the appeal, judges ordered the bank to pay Mr Allen's legal costs and refused it permission to take the case to the Supreme Court.
Lord Justice Wall said Mr Allen could not access counter facilities at the bank and a duty "plainly thereby arose" under the Disability Discrimination Act.
The judge said the bank could have taken steps to provide access for those suffering from disabilities.
Mr Allen's mother said he was forced to carry out transactions in the street
"The bank did not take those steps, giving as its reason not the disproportionate cost of carrying out the work, but simply the fact that it would lose the use of an interview room," he said.
Speaking after the judgement, Mr Allen said: "I'm glad the bank finally had to apologise in court and acknowledge they treated me badly.
"They just failed to understand anything about the need for privacy and dignity."
Mr Allen's mother Ceri said: "This is just such good news for disabled people.
"RBS claim to take disability issues seriously. They actually told the court that David received better treatment than other customers because they allowed David to carry out banking transactions in the street.
"The everyday reality for wheelchair users is that level access or lifts are still all too often not available.
"The only reason we brought the claim was because they thought they could ignore us."