First Direct, the online arm of HSBC, the UK’s largest bank, is to levy a £10 monthly fee on its current accounts. Only customers who deposit £1,500 a month or who maintain an average balance of £1,500 will escape the fee.

Financial commentators said that the move would herald a rush by other banks to do the same. NatWest and Lloyds TSB said last night that they had no plans to introduce fees to their current accounts, but refused to rule it out.

First Direct’s move will come as a blow to pensioners, women on maternity leave and others who have low or fluctuating incomes, who may struggle to meet the stringent requirements. A First Direct spokesman said that around 200,000 of its 1.3 million customers would have to shoulder the extra fee when it is introduced next February.

Which?, the consumer organisation, said that the charge would penalise those on lower incomes. “It is a shame that customers not in a position to keep £1,500 in their account at all times are being penalised,” a spokesman said.

Alan Duncan, Shadow Trade and Industry Secretary, said: “This is an irrational basis for charging. This is simply a tax on the lower-paid which will prevent access to bank accounts. I cannot see any way in which this is fair or justified.”

John McFall, Labour chairman of the Commons Treasury Select Committee, said the £1,500 figure was a high hurdle and did nothing for those who were financially excluded. There should be an honest debate about the concept of free banking, he said.

Several banks charge up to £15 a month for packaged or premium current accounts, which come with perks such as free travel insurance or cut-price currency exchange. But they also offer free current accounts.

First Direct’s announcement comes just weeks after the Office of Fair Trading said that it would investigate current account charges, prompting experts to predict an end to free banking.

Banks make nearly £5 billion a year from unauthorised overdraft charges. The OFT is investigating whether to cap these fees. Defaqto, a financial pro-ducts research business, said that any cap could signal an end to free current accounts as banks try to claw back the money they lose.

Customers will need to earn at least £24,000 a year before tax to meet First Direct’s minimum funding requirement of crediting £1,500 a month. But the bank says that people who earn less than this can have the fee waived by taking out another of its products, such as a credit card or mortgage.

Which? said: “This move will certainly alienate many thousands of customers unfairly targeted for choosing to have products with other providers who may be more competitive.”

First Direct charges between 15.9 per cent and 19.9 per cent interest on its credit cards. Other banks charge less: Intelligent Finance charges 8.9 per cent on its flatrate Visa, while Co-operative Bank charges 9.9 per cent on its Clear Visa card.

David Black, head of banking at Defaqto, said: “First Direct has created a sort of halfway house of a fee-charging account and we are going to see a stream of similar accounts in the future. They are trying to corner the affluent end of the market.” HSBC, First Direct’s parent, said that it had no plans to follow the online bank’s example.

The OFT is expected to report early next year.