Dame Alison Rose said she made a "serious error of judgment" when she discussed the former UKIP leader's relationship with private bank Coutts, owned by NatWest Group, with a BBC journalist.

The NatWest Group board is meeting now to discuss the future position of Dame Alison as chief executive.

Sky News' City editor Mark Kleinman said it is "expected" the boss will step down from her role, but "no final decision has been taken".

Mr Farage has accused the bank's management of a "serious breach".

He told Sky News: "I think her position is totally untenable. Anybody, even a junior clerk in the bank, if they breached the confidence of a customer would have to go... I don't believe for a moment she will be there by the end of Friday."

His call was echoed by Tory former cabinet minister David Davis, who said Dame Alison had "little choice but to resign".

The chairman of NatWest, Howard Davies, said there have been "serious consequences" for the bank as a result of the "unsatisfactory" handling of the closure of Mr Farage's account.

The story first came to light when the BBC inaccurately reported Mr Farage's account was closed as he did not meet Coutts's financial thresholds.

Documents obtained by Mr Farage subsequently showed his political beliefs and connections formed part of the rationale.

The BBC, on Monday, apologised for the report.

Dame Alison said she believed it was public knowledge that Mr Farage was a Coutts customer and had been offered a NatWest account, and so confirmed these details to BBC business editor Simon Jack.

She said she repeated the Coutts stance - which Mr Farage had publicised - that the bank saw the account closures as a commercial decision.

"I would like to emphasise that in responding to Mr Jack's questions I did not reveal any personal financial information about Mr Farage," she added.

"In response to a general question about eligibility criteria required to bank with Coutts and NatWest I said that guidance on both was publicly available on their websites.

"In doing so, I recognise that I left Mr Jack with the impression that the decision to close Mr Farage's accounts was solely a commercial one."

Dame Alison said at the time of her conversation with Jack she had not seen the material behind Coutts's decision to close the accounts and was not part of the decision-making process to close the accounts.

Instead, she said, Coutts told her in April Mr Farage's account was being closed for commercial reasons.

"Put simply, I was wrong to respond to any question raised by the BBC about this case."

As well as calling for Dame Alison to resign, Mr Farage said Coutts chief executive Peter Flavel must take "the ultimate responsibility for de-banking me based on my political views".

He added that Sir Howard Davies, chairman of Natwest Group, "is responsible for overall governance. He has clearly failed in this task, least of all by endorsing their conduct."

"In my view - they should all go."

The NatWest board said it believed it was "clearly in the interest of all the bank's shareholders and customers" that Dame Alison continued in the role.

"She has proved, over the last four years to be an outstanding leader of the institution, as demonstrated by our results," Mr Davies said.

Findings of the NatWest review into the closing of Mr Farage's accounts will be made public and the terms of reference will be announced shortly, the NatWest announcement said.

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The banking regulator said it had raised concerns with the NatWest Group about the breach of customer confidentiality.

"We made clear our expectation that these issues should be independently reviewed and note today's statement from the NatWest group board confirming this will happen," the Financial Conduct Authority said.

"It is vital that the review is well resourced and those conducting it have access to all the necessary information and people in order to investigate what happened swiftly and fully."

NatWest is 38.6% taxpayer-owned after state bailouts during the global financial crash.