I can reveal that the bank is preparing to say in its full-year results announcement next Thursday that it is increasing its provision for mis-selling interest rate swaps by roughly £700m, which will take its cumulative bill to £750m.
City sources say that RBS will also announce that it is raising its payment protection insurance (PPI) mis-selling bill by just over £400m, meaning it will have put aside just over £2.1bn for its part in the industry-wide scandal.
The new provisions will further elevate the total bill for Britain's biggest banks from two of the sector's biggest mis-selling episodes. RBS's new PPI charge will mean that the four major lenders have had to provide more than £11bn for compensation, while its hit on interest rate hedging products will enlarge the industry bill to £1.6bn.
Neither of those figures will, however, include imminent upward revisions in both categories by both HSBC (LSE: HSBA.L - news) and Lloyds Banking Group (LSE: LLOY.L - news) , which also report full-year results in the next ten days.
Both RBS and Lloyds, which are 82% and 39% owned by British taxpayers respectively, will report losses for 2012.
RBS is also expected to confirm that it is examining a separation of its US retail banking business, Citizens (NYSE: CIA - news) , through a stock market listing in the US, in a move that over time could raise billions of pounds for the British lender.
George Osborne, the Chancellor, is likely to welcome the move when he appears in front of the Parliamentary Commission on Banking Standards on Monday.
Both Mr Osborne and David Cameron have been increasing the pressure on RBS's management, led by chief executive Stephen Hester, to accelerate the group's restructuring.
Mr Hester is expected to respond next week by pointing to a further retrenchment of its investment banking operations. RBS, he is understood to be preparing to say, will continue to reshape its operations into a British retail bank that is also able to support the international business objectives of core UK clients.
The new provisions for PPI and swaps mis-selling will reflect ongoing claims trends and the recent agreement between the major banks and the Financial Services Authority to offer redress to small business customers according to a defined framework.
The major banks have grudgingly accepted the swaps settlement with the City regulator although they have argued that many of the cases for which they will have to pay compensation should not be categorised as mis-selling.
They have also pointed to the vast numbers of bogus PPI claims they have received, many of which have been paid out anyway. The industry has been discussing the imposition of a time limit on PPI mis-selling claims although at least one major bank is lukewarm about the idea.
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