RBS first to warn firms to prepare for charges on deposits

Such a development would mean that the still 73 per cent state-owned lender would be the first UK bank to introduce negative interest rates, in effect, charging to deposit money.

The charges would also affect business customers of Natwest, the subsidiary of the Edinburgh-based lender, but not personal customers of either bank.

In a in a letter to its business customers, which range from self-employed traders, charities and clubs to big corporations, RBS Group said: “Global interest rates remain at very low levels… this could result in us charging interest on credit balances.”

A spokesperson for RBS said the letter was sent to just under 1.3 million of the combined business and commercial customers of both it and its Natwest bank.

They added: “We will consider any necessary action in the event of the Bank of England base rate falling below zero, but will do our utmost to protect our customers from any impacts.”

The Federation of Small Businesses, which has 170,000 members, called on other banks to update customers of any changes to their Business Current Account (BCA) “during this uncertain economic period”.

Mike Cherry, National Chairman at the FSB (FSB), said the warning from Natwest and RBS “will be deeply concerning to small firms”.

UK interest rates have been unchanged since the Bank of England cut them to a record low of 0.5 per cent in March 2009 at the height of the financial crisis and the FSB urged the BofE to consider the impact on smaller firms of cutting base rates yet further.

But bank governor Mark Carney has already said it is likely “some monetary policy easing” will be required to boost the UK economy in response to the Brexit vote although not to the extent of any lower than 0.25 per cent.

The reassurances, though, have not stopped speculation among analysts and the City is expecting an impenitent cut from the already historic low of 0.5 per cent.

Mr Cherry said that the warning by the bailed-out bank was deeply concerning to small firms and suggested customers should look around for the best accounts on offer.

He said: “FSB’s latest research shows small business confidence is already at a four-year low. Firms are less optimistic, cutting headcount and curbing investment intentions.”

The next opportunity for the Bank of England’s monetary policy committee to cut interest rates is on 4 August, and addressing the MPC directly, Mr Cherry said: “When the monetary policy committee meets next week to decide on interest rates, we would call on them to do everything possible to consider the implications of changing interest rates for smaller firms and the self-employed looking to maintain or grow their business.”