Customers of UK bank NatWest were unable to withdraw cash or use online and telephone banking services last night following a fresh IT outage.

A spokesperson for the bank told Information Age that the outage was caused by a hardware failure.

It has been reported that “the majority” of NatWest customers were affected, but that has not been confirmed by the bank.

“We are disappointed that our customers have faced disruption to banking services for a period [yesterday] evening, and apologise for that,” NatWest said in a statement. “All services are now running as normal again.”

It is the second major outage affecting NatWest customers in less than a year. The bank suffered prolonged IT service interruption last year following a botched software upgrade by parent group RBS. The IT outages cost the bank at least £175 million, mainly in compensation for affected customers.

The new blow for RBS came as Mervyn King, governor of the Bank of England, called for the majority state-owned bank to be split into two divisions – one that manages RBS’s bad debts, which would be retained by the tax payer, and another that would be free to increase lending.

“The whole idea of a bank being 82% owned by the taxpayer, run at arm’s length from the government, is a nonsense,” King said yesterday, as he gave evidence to the Commons’ banking standard committee. “It cannot make any sense”.