RBS, Lloyds, HSBC and Barclays still facing £19bn in scandal costs - S&P

The latest hit would take the total paid out by Barclays, HSBC, RBS and its fellow bailed-out, Edinburgh-based lender, Lloyds, since 2011, to more than £75bn.

The new S&P report comes as the big four banks prepare to publish their first-quarter results, which are expected to include further PPI provisions.

The ratings agency said that over the five years to 2015, the quartet of financial giants have together incurred costs of £55.8bn to cover so-called conduct and litigation issues, after being penalised for rigging Libor and foreign exchange markets, and having to compensate customers for misselling payment protection insurance.

“This staggering amount represents around 9 per cent of these banks’ revenues during this period and about 90 per cent of all conduct and litigation charges for the UK banking system,” S&P said.

The total cost of the scandals for the UK banking industry was £62.5bn, S&P said.

While the ratings agency is now predicting charges of £19.5bn by the end of 2017, it also describes this year as the “last year for mega charges”. This is, in part, because of an expectation that the cost of the PPI scandal, which has reached £34bn, will ease off.

“We maintain our view that 2016 will likely be the last year for mega conduct and litigation charges. That said, we also believe that conduct and litigation matters have become a ‘way of life’ for UK banks,” S&P said.

“We do not believe that future retail conduct redress, including relatively new issues such as packaged bank accounts, will come close to the scale of PPI,” it added.