She got a lot of flak for being the source of a false BBC story about a leading Brexit supporter’s account at NatWest Group’s Coutts bank.

Howard Davies, the head of NatWest, said that she was going on good terms.

Dame Alison said she had made a “serious mistake.”

NatWest Group chairman Sir Howard Davies said in a statement released early Wednesday morning, “The Board and Alison Rose have agreed, by mutual agreement, that she will step down as CEO of the NatWest Group. It makes me sad.

“She has worked for NatWest her whole life and will leave behind a lot of coworkers who respect and admire her.”

NatWest’s board of directors said that Paul Thwaite, the current CEO of the company’s Commercial and Institutional business, would take over Dame Alison’s duties for an initial time of 12 months, pending regulatory approval.

In a separate statement, Dame Alison thanked her coworkers “for all that they had done” and said, “I remain incredibly proud of the progress the bank has made in helping people, families, and businesses across the UK and laying the groundwork for sustainable growth.”

Earlier, she apologized for talking to a BBC journalist about the closing of Nigel Farage’s account at NatWest’s private banking arm Coutts. She said it was a “serious error of judgement”

This apology came after the BBC said it was wrong when it said, based on a person familiar with the situation, that Mr. Farage’s account was being closed because he no longer met the wealth threshold for Coutts.

BBC News was told that on Tuesday night, Downing Street and Chancellor Jeremy Hunt had “significant concerns” about how she had been acting.

The former head of the UK Independence Party, Mr. Farage, first said that his account had been closed at the beginning of July.

Dame Alison first said she was engaged when she told BBC business editor Simon Jack that “she had confirmed that Mr. Farage was a Coutts customer and that he had been offered a NatWest bank account.” She said she thought everyone knew about this.

The head of NatWest said she had not told anyone about Mr. Farage’s personal finances.

“In answer to a general question about who can bank with Coutts and NatWest, I said that information about both could be found on their websites.

“I know that by doing that, I gave Mr. Jack the impression that the decision to close Mr. Farage’s accounts had nothing to do with business,” she said.

She also said, “It was a mistake for me to answer any question the BBC asked about this case.” I want to apologize to Mr. Farage for the hurt this has caused him on a personal level, and I have written to him today.

Mr. Farage said that Coutts didn’t tell him why it closed his account when it did.

But Mr. Farage had gotten a paper that said why Coutts should work with him.

The document worried that he was “xenophobic and racist” and calculated the risk to the company’s image of having Mr. Farage as a customer.

Dame Alison said that Coutts told her that the account was closed because it was bad for business.

She told Simon Jack of the BBC that she hadn’t seen the report that Mr. Farage had gotten.

NatWest plans to share its financial results for the first half of the year on Friday. This will be followed by a presentation to management.