Battered workers at Royal Bank of Scotland (RBS) reeled once more yesterday as the bank's executive class leaked news of thousands more layoffs starting month.

Staff union Unite reacted with alarm after reports surfaced of a £1 billion cuts plan - with ordinary clerks and tellers allegedly in the cross-hairs.

Sources published in the Herald and described as "colleagues" of chief executive Ross McEwan said yesterday they expected "very substantial" layoffs when the bailed-out bank proffers its annual results in February.

RBS posted losses last quarter of £720 million before tax.

Sources said Mr McEwan has pushed plans to replace its high street branches' customer service staff with touchscreens and other automated technologies.

The bank has already axed 40,000 jobs since the financial crisis began in 2008 - a full third of its payroll.

Yet barely one in eight of culled jobs are from the firm's investment arm, despite its pivotal role in the economic meltdown and the Libor affair - the biggest market-rigging scandal in financial history.

Unite national finance officer Dominic Hook yesterday described the reports of further job losses as "very worrying."

The union's members had borne the brunt of management's mistakes and enough was enough, he fumed.

"Many of our members earn as little as £16,000 a year and this has gone hand-in-hand with increased workloads, unpaid overtime and great pressure," said Mr Hook.

"We call on the RBS management to engage with Unite in a constructive fashion over its future plans and acknowledge that an organisation's greatest asset is its people."

Mr McEwan took up the bank's top job last August in what Tory Chancellor George Osborne described as an attempt to put "the mistakes of the past behind it."

But regulators have continued to grill the bank's investment arm amid an international investigation into rigged currency exchange rates.

It is alleged traders at a number of banks used instant messaging software to ask colleagues to falsify their data in a setup similar to the Libor-fixing scandal exposed in 2012.

Regulators have said the tactic would affect trillions of pounds' worth of transactions and contracts.