The body received a total of 133,019 cases between January and June, up 43% on a year ago.

However, mortgages and home finance grievances fell 26% to 3,685 cases over the same period.

Chief ombudsman and chief executive Abby Thomas says: “Businesses should put consumers at the heart of their service but the high level of complaints we receive shows that’s not always the case.

“It’s vital that businesses are open and transparent with their customers, treating them with fairness and understanding.”

Banking and credit cases drew the largest volume of complaints and fuelled the rise in overall grievances with 101,031 disputes, jumping 78% from the previous 12 months.

This was followed by general insurance and pure protection cases, which came in at 24,496, down 8% in the period.

Mortgages and home finance disputes were third on the list of financial services complaints.

Simplify Consulting lead consultant Dom House labels the figures “extremely disappointing”.

House says: “Firms should now be looking at their complaints data to understand how they can reverse this trend and consider whether the changes they’ve made for Consumer Duty have had the impact intended.

“Consumers expectations have been raised as new technology becomes mainstream in the financial services industry and firms need to get a grip by addressing the imbalance between prevention and cure by focusing on the root cause and prevention of complaints before they are raised.”

He adds: “Consumer Duty has made complaints more visible to senior leadership in firms. This is a positive, and increasingly we are seeing firms not just reviewing the complaints numbers periodically, but taking a closer look at how the complaints function interacts with the rest of the business.

“Those that can build an effective complaints strategy, will not only be delivering better outcomes for clients and be meeting Consumer Duty requirements, they might well reduce the risk of losing a large proportion of their clients.”