According to a confidential Group Internal Audit report passed to Your Money’s sister publication Mortgage Solutions, it was unclear in 89 cases whether RBS customers received compliant advice, a suitable mortgage or a fair outcome.

Back in 2011, after a mystery shop, the Financial Services Authority flagged problems with RBS over the quality of its branch mortgage advice.

In a letter dated 4 November 2011, the regulator asked it to carry out a Risk Mitigation Programme action, or assess its branch, direct and live-observed advised mortgage sales to see if the problems had been resolved.

The confidential report, dated 10 September 2012, was intended to show the progress the bank had made subsequently.

However, the 91 sample checks carried out between January and July 2012 revealed just two telephone advice cases passed, with the other 89 cases divided between three fail categories.

From the sample, 28 cases had one or more key failures in the sales process, 56 cases failed to demonstrate product suitability or a fair customer outcome and in five cases, the recommended products were not suitable or affordable, the sale was uncompliant and the customer had not received a fair outcome.

The report that followed dated 10 September 2012 showed the assessment criteria was based on affordability; mortgage term; debt consolidation; suitability into retirement; switching loans and additional borrowing and adequacy of record keeping.

The bank, which is still 83% taxpayer-owned said the failures were solely a record keeping issue.

An RBS spokesperson said: “Of the 91 sales we looked at, we found record keeping to be lacking in all but two cases. That was a big disappointment, but does not mean mistakes were made with the sales.

“To make sure we decided to contact customers directly to review their cases. In all but one case of the 91 we looked at we found that this had been strictly an issue of record keeping and customers were all on the right product.”

Since the review in September 2012, the bank said all of its advisers had received scheduled training in preparation for the Mortgage Market Review (MMR) implementation in April 2014.

It added in March, 63% of a sample of the bank’s mortgage customers said they would recommend its service to friends and family.

New regulator, the Financial Conduct Authority refused to be drawn on RBS, but it confirmed providers with a history of problems are monitored more closely than others.