The largest number of complaints were lodged against Barclays Bank with 739 new cases, followed by Bank of Scotland with 524 cases, and Santander taking third spot with 418 cases, says the industry arbitration service.  

The data covers the six months to 30 June, a month before the Financial Conduct Authority’s sweeping Consumer Duty rules came into force on 31 July.  

It adds that 28% of complaints in this sector were upheld, which is lower than the overall average of financial industry complaints made in this period at 37%.  

Across the industry, the body saw complaints lift 16.5% to 93,114 in the first half of the year, which it says is “significantly higher” than the last six months of 2022.  

Banking and credit disputes attracted the most complaints with 56,690 new cases, followed by the general insurance sector with 24,496 cases, and the mortgage business in third place.  

The ombudsman blamed several reasons for the rise in complaints across the industry. 

It says over the last three months building and motor insurance complaints hit a five-year high, partly due to insurers delaying in paying out on claims, while at the same time the availability of car mechanics slowed the speed of repairs.   

The service adds that banking and credit complaints have “risen substantially with fraud and scam cases making up around half of that increase”.  

Financial Ombudsman Service chief executive and chief ombudsman Abby Thomas says: “Financial complaints have risen again, with cases particularly increasing in the banking and insurance sectors.  

“Given the economic challenges people are facing, it’s more important than ever that they feel protected.   

“Whatever their grievance, consumers should expect fair and reasonable treatment from their provider.”