THE former North Yorkshire schoolboy who heads banking giant RBS has tonight apologised for glitches which left customers unable to pay bills or withdraw cash.

The company's chief executive, Stephen Hester - who was once head boy at Easingwold School during his seven years as a pupil there - said nobody would be left "permanently out of pocket" after the technical fault which disrupted payments to and from NatWest, RBS and Ulster Bank.

The fault, caused by a computer software problem, has now been fixed, but NatWest will still open 1,200 branches on Sunday to clear the backlog they caused.

Mr Hester said: "Our customers rely on us day in, day out to get things right. On this occasion, we have let them down.

"I also want to to be clear that where our customers are facing hardship and difficulty, we can and will help them. Our staff have already helped thousands of customers to access cash and we will continue to provide this service on a 24-hour basis while we work to resolve the problems.

"I also want to reassure customers that nobody will be left permanently out of pocket as a result of this and, again, they should contact us directly about this."

The problem is believed to have started after staff tried to install a software update on RBS' payment processing system, but instead corrupted it. The resulting backlog means NatWest will open on Sunday for the first time in its history, from 9am until midday. More than 1,300 NatWest, RBS and Ulster Bank branches stayed open late today.

Mr Hester said the bank had doubled its usual tally of call-centre staff, adding: "My top priority, and the priority of the entire RBS Group, is to fix these problems and put things right for our customers.

"Once again, I am very sorry for the inconvenience."

The Financial Ombudsman Service has advised anybody affected by the problems to keep a record of how they were financially disadvantaged, and said anybody unhappy with their bank's response to their concerns could make a complaint to the Ombudsman. Banks are obliged to return customers affected to the financial position they should have been in if a problem had not occurred.