The action plan, which builds on progress already underway, sets out how the OBS will change and improve, how we will deliver for all its customers and provide fair and reasonable financial dispute resolution more quickly.

The action plan focuses on five key themes:

• A new operating model to meet a changing environment, making it more effective and efficient to resolve cases more quickly.
  Enhancing technology and digital capabilities, to drive productivity and to make it easier and more efficient for customers to choose how they interact with the Financial Ombudsman Service.
• Boosting engagement with our stakeholders and taking a robust and proactive approach to prevent complaints and unfairness arising to ensure that we solve problems together efficiently.
• Developing the current strategy to further enhance the Financial Ombudsman Service, using insights from timely case handling to prevent further harm to consumers.
  Exploring revisions to our funding model to ensure a sustainable future.

The announcement comes off the back of a report conducted by Oaklin Consulting, which found that individuals making a complaint about financial firms have been left waiting years for justice.

The report found 1,800 unresolved cases that were more than three-years-old, with some extending beyond the four-year mark. There were 13,000 cases between one and two years old and 3,100 cases between two and three years.

The report said such delays were “obviously detrimental” to consumers, particularly the financially vulnerable. In some instances complainants had missed the opportunity to pursue a case in the courts because of the delays.

Oakling Consulting found that cases took an average of five months to be allocated to an investigator and more than 14 months to be resolved. The OBS is supposed to resolve complaints within three months.

Alongside the backlog of complaints, the OBS has become less efficient. In 2015, it cost £64m to resolve 119,400 cases, or £535 per case, but last year it cost £111m for 139,800 cases, or £795 per case.

The report found that the service needed a 36pc gain in productivity.

Nausicaa Delfas, OBS interim chief executive and chief ombudsman, added: “The Financial Ombudsman Service is at a pivotal point. The action plan is our commitment to continue to make the changes we need to resolve customer complaints more quickly.

“We will be changing our operating model, leveraging technology, and ensuring we share our insights to prevent complaints from arising in the first place. This builds on the work we have already done to almost halve our backlog so far this year.

“This review has given us the opportunity to reset and move forward, and we are determined to seize it.”