The Financial Ombudsman Service (Fos) has admitted it failed to "get to grips" with nearly one in 10 of the cases it handled in 2018.
In a letter to the Treasury select committee dated February 7, Caroline Wayman, chief executive of the Financial Ombudsman Services, said quality review checks flagged the organisation may not have got to grips with issues in 8 per cent of cases.
The letter followed the ombudsman's appearance before the Treasury select committee to give evidence on how the service deals with customer complaints.
The letter stated: "Our quality assurance framework and reporting helps us understand how well we are doing in providing a quality service to our customers, including whether we’re reaching fair outcomes.
"One of our core questions asks whether we 'got to grips with the issues' in a case.
"In the 12 months January to December 2018, in completing the 'getting to grips' check as part of our quality assurance process on cases across the service, we didn't agree that we had in around 8 per cent of cases."
However Ms Wayman added that this does not mean an outcome was necessarily wrong, but means the quality reviewer had some doubt about how well Fos had done.
She wrote: "It may also include examples where we reached a fair outcome, but may not have handled the case as well as we could have, for example, if we initially overlooked an important issue or piece of evidence, but then subsequently corrected this."
Fos stated it does not specifically record how many case outcomes have changed following a quality review.
However, where a quality assessment does identify a potential issue with an outcome, Ms Wayman said the ombudsman will look at the case again to ensure it is handled appropriately.
Dean Mullaly, director of Mark Dean Wealth Management, welcomed the ombudsman's admission.
He said: "I'd be more worried if Fos said they were 100 per cent on top of things all the time. It is good they are being honest.
"No organisation can say they are getting things perfect at all times. I expect Fos is being inundated with claims as we are getting more like the US in terms of the claims culture.
"If Fos is aware of the issues and how it can improve, this is a good thing."
Dippy Singh is a freelance journalist