These include the abolition of two-stage complaints to make sure firms do not dismiss complaints straight away and the identification of a senior individual within firms to handle complaints.

The FSA will also provide guidance for firms to help them understand the processes of root cause analysis and how firms should take account of ombudsman decisions.

The limit on awards made by the ombudsman services has also increased from £100,000 to £150,000.

Sheila Nicoll, FSA director of conduct policy, said: “We would rather customers were not put in the position where they had to complain, but when they do we want them to be treated fairly by their firm, with their complaint resolved promptly and being provided with redress when needed.”

Since 2009 the FSA has published complaint statistics enabling customers to compare and contrast the handling procedures of different firms.

The FSA has already fined two large banks for their complaint handling procedures.

Bank of Scotland were fined £3.5m for complaints related to retail investment products while Royal Bank of Scotland and Natwest were fined £2.8m for multiple complaint handling failures.

Ms Nicoll said: “Good complaints handling contributes to customer loyalty and should provide the opportunity for firms to put right problems in product design or sales before issues become widespread.

“But we have found major failures related to the way firms handle customer complaints and have since taken enforcement action against two firms as a result of poor complaints practice.”