Royal Bank of Scotland (RBS) has become the latest corporation to toss the remnants of its reputation on to the scrapheap of litigation.Having lost in the Court of Appeal last week, RBS is now seeking permission to appeal to the Supreme Court against a January 2009 ruling at Sheffield County Court that it was in breach of the Disability Discrimination Act and should install a wheelchair lift in one of its Sheffield branches.

A spokesman for RBS said: ‘The Royal Bank of Scotland Group plc is committed to meeting its obligations under the Disability Discrimination Act 1995 and the requirements of its disabled customers. The Bank firmly believes that it met such obligations in this instance and has applied for permission to appeal to the Supreme Court.’

But is it really in the bank’s best interests to continue fighting this case? The estimated cost of the installation is £200,000. RBS has also been told to pay £6,500 plus interest for injuries to the feelings of a disabled customer, 18-year-old David Allen, who has muscular dystrophy and who brought the action because he was unable to gain access to his local branch of the bank.

That adds up to a lot of money to you and me. It would even make a dent in former RBS chief executive Sir Fred Goodwin’s pension – now reduced from £703,000 a year to a more modest £342,500.

But why can RBS not see that, in the eyes of the public, the bank is awash with cash? This is a bank that is 84% owned by the taxpayer and that earlier this month accepted an extra cash injection from the government of £25.5bn. And then there’s the aforementioned pension for Sir Fred.

Did it not occur to anyone at the bank that fighting a disabled teenager through the courts was not going to endear it to its customers? Could nobody see that it would be both politic and affordable to play Mr Nice Guy?

RBS is not alone in shooting itself in the foot. Fast food giant McDonald’s runs a charity called Ronald McDonald House Charities, which was established in 1989, is active in 50 countries worldwide and provides free accommodation for families whose children are in hospital. In the UK alone, it has 12 houses and 350 family bedrooms available. The wife of the McDonald’s founder donated $60m to it in 2003, so there’s no doubt it is serious about making the charity a success. Forget the golden arches – these guys deserve a halo.

Except McDonald’s still contrived to blow all its credibility – not to mention bucketfuls of money – on what has been described as the biggest corporate PR disaster in history.

It was the case of the McLibel Two, when McDonald’s took a part-time barmaid and a single parent on income support to court in a 313-day trial that ended in February 2005. The pair were accused of defamation. They had to represent themselves, albeit with pro bono help from sympathetic lawyers. The McDonald’s legal team, on the other hand, was headed by a £2,000-a-day libel QC. And McDonald’s lost.

What madness drives otherwise sensible corporations do these things?