Taxpayer-backed Royal Bank of Scotland racked up more than £300 million worth of charges on Friday as it counted the cost of an IT meltdown and two mis-selling scandals.

The 80 per cent state-owned bank set aside £125 million for dealing with the fallout of the computer glitch that locked many RBS, NatWest and Ulster Bank customers out of their accounts.

The group took a £135 million hit to cover the cost of payment protection insurance (PPI) mis-selling, bringing its total bill to £1.3 billion.

It also took a £50 million charge to compensate small businesses that were mis-sold complex interest rate swaps.

The mounting provisions came as the bank, which has 30 million customers worldwide, unveiled a pre-tax loss of £1.5 billion, compared to a £794 million loss last year.

But RBS boss Stephen Hester said: "We have continued to make the bank safer and stronger as we clean up problems of the past."