Royal Bank of Scotland has welcomed a report by a law firm that found no evidence of it systematically defrauding its customers and has promised to overhaul the way it handles small and medium-sized businesses in financial distress.

The review by Clifford Chance was ordered by RBS in response to allegations made last year by Lawrence Tomlinson, an adviser to the UK business secretary Vince Cable, that the bank sought to profit from harming rather than helping small business customers.

Chief executive Ross McEwan said: “I welcome the . . . findings which show no evidence of the serious and damaging allegation that we had set out to deliberately defraud our business customers.”

Clifford Chance said it interviewed 138 small business customers and reviewed 130 files, of which a “substantial proportion” involved businesses that wished to complain about the way they were treated by RBS. It also spoke to 45 RBS staff.

Mr Tomlinson said he had not accused the bank of fraud. “It’s important to note that Clifford Chance did not investigate or reach conclusions on areas such as the validity of valuations and treatment of businesses,” he said. – (Copyright The Financial Times Limited 2014)