Royal Bank of Scotland will set aside a provision of £850m to compensate customers for the mis-selling of payment protection insurance (PPI).

The bank revealed in a stock exchange announcement yesterday evening that it would not appeal the judicial review decision relating to PPI and that the £850m charge would be taken against its second-quarter results.

RBS said to date it has already paid PPI compensation of around £100m, and has an existing provision of £100m.

Last Friday, when the bank announced its first-quarter 2011 results, it refused to estimate how much PPI mis-selling would cost it.

Rival banking group Lloyds announced last Thursday that it had set aside £3.2bn for PPI mis-selling compensation, tipping the bank into a £3.47bn loss for the first quarter of 2011. Yesterday Barclays set aside 1bn.