Nearly half a billion pounds of fresh writedowns related to financial guarantors detracted from strong growth in Royal Bank of Scotland’s global banking and markets business and pushed operating profits last year down 2% to £3.7bn (€4.9bn) from the previous record year.

The £456m in additional valuation writedowns came in response to “the weakening credit profile of certain financial guarantors”, and came on top of already announced writedowns on sub-prime and leveraged finance positions, RBS said today in its full-year results presentation.