Dr Tomlinson's report for business secretary Vince Cable earlier this year accused RBS of systematically pushing struggling small firms into its Global Restructuring Group (GRG) unit, so it could charge higher fees and interest, and take control of their assets.
RBS is now reported to have said it cannot rule out legal action after being "cleared" of the report's most damaging allegations. The report published last week was commissioned by the bank from Clifford Chance, one of the bank's legal advisers. Jon Pain, RBS head of regulatory affairs, says it found no evidence of fraud and only "a handful of cases found allegations of poor staff behaviour".
However Dr Tomlinson told the Sunday Herald: "The Clifford Chance report does not exonerate RBS. That seems to be a deliberate misdirection away from Clifford Chance's real findings."
The Herald has highlighted three separate ongoing court actions involving Scottish developers and GRG, while a fourth action is headed for the Supreme Court. The Financial Conduct Authority is conducting its own investigation into RBS's conduct, the independence of which was welcomed by the Federation of Small Businesses.
The RBS GRG Action Group said the bank's conduct was "best judged by the regulatory authorities...and in court".