Reports in the UK media suggest that a number of the leading high street banks could face action from the industry regulator if they do not improve the way they deal with consumers' complaints.

The threat emanates from a report issued by the Banking Codes Standards Board (BCSB), another industry watchdog, which has noticed a rising tide of unhappiness among consumers dissatisfied with their banks’ handling of complaints.

The BCSB oversees the Banking Code, a voluntary set of guidelines intended to introduce uniformity among retail banks about how customer grievances are handled. The BCSB says that one in ten approaches it received in the first three quarters of 2005 were about mis-handled complaints, a marked rise on the typical one in 50.

The BCSB has suggested that the banking regulator, the Financial Services Authority, could now get involved to ensure banks are treating customers fairly.

The Financial Times reports that this is unlikely to please the major banks, which are already smarting from the threat of enforcement action from the FSA to cap credit card, mortgage and overdraft fees.