The Central Bank of Ireland has slapped Ulster Bank with a record €3.5m fine over a serious breakdown of its IT systems in mid 2012. The breakdown prevented customers from accessing their accounts for nearly a month.

Around 600,000 customers were deprived of essential and basic banking services over a 28 day period, between June and July 2012, due to a glitch in the RBS CA-7 batch process scheduler that blocked 12 million accounts.

Central Bank director of enforcement Derville Rowland said: "The IT failure caused significant and unacceptable inconvenience to affected customers trying to carry out their everyday financial transactions.

"Over a prolonged period of time customers were unable to access cash through ATMs/cash and pay for goods and services and there was a delay in the processing of payments in and out of accounts.

"As the provision of financial services to customers represents the core business function of the Firm, the major breakdown in the Firm’s provision of these services as a result of IT failings is completely unacceptable."

The latest fine and reprimand are in addition to the €59m being paid to consumers.