COUTTS the private bank owned by Royal Bank of Scotland, has warned thousands of customers they may have been exposed to unsuitable investments.

The bank is to review all advice given before November 26, 2012, when it changed its procedures to meet new Financial Conduct Authority rules.

In a letter to UK clients, Coutts chief executive Michael Morley says there were "some instances where the advice given during our previous advice process could have been better" and where clients had suffered detriment, portfolios would be adjusted and full compensation paid.

It said electronic records had removed a "weakness" stemming from paper records.

A spokesman for RBS confirmed its Scottish-based private bank Adam & Co was not affected by the issue.