The Bank of England’s newly-appointed deputy governor has resigned after coming under fire for breaking the Bank’s code of conduct by failing to declare that her brother worked for Barclays.

Charlotte Hogg offered a voluntary resignation last week, before insisting in a letter to Bank governor Mark Carney on Monday that she must step down from her post.

Her resignation letter was made public on Tuesday, just moments after the House of Commons Treasury Select Committee published a report stating that her “professional competence falls short” of the standards required to fulfil her role as deputy governor of the Bank.

Writing to Mr Carney and Anthony Habgood, chairman of the Bank’s Court, Ms Hogg said: “Last week I offered you my resignation in recognition of the fact that I made a mistake in not declaring my brother’s work on the forms that the Bank requires. It has become clear to me that I should now insist.

“As I have said, I am very sorry for that mistake. It was an honest mistake: I have made no secret of my brother’s job – indeed it was I who informed the Treasury Select Committee of it, before my hearing.

“I accept it was a mistake, made worse by the fact that my involvement in drafting the policy made it incumbent on me to get all my own declarations absolutely right. I also, in the course of a long hearing, unintentionally misled the committee as to whether I had filed my brother’s job on the correct forms at the Bank. I would like to repeat my apologies for that, and to make clear that the responsibility for all those errors is mine alone.”

Ms Hogg had apologised to the Committee for not formally disclosing that her brother, Quintin, was Barclays’ group strategy director, which could conflict with her work on the Prudential Regulation Committee (PRC).

She had failed to declare the family link on a number of occasions since joining the Bank as chief operating officer in 2013.

It comes after Ms Hogg, who has been touted as a possible successor to Mr Carney, told the Committee at a hearing that she always declared areas of conflicts of interests and was compliant with all of the Bank’s codes of conduct because she helped to write them.

It prompted committee member John Mann to demand she should step down, saying that Ms Hogg “has either lied to Parliament or she is grossly incompetent”.

In response to her resignation letter, Mr Carney said: “While I fully respect her decision taken in accordance with her view of what was the best for this institution, I deeply regret that Charlotte Hogg has chosen to resign from the Bank of England.

“Since Charlotte joined the Bank almost four years ago, she has transformed its management and operations.

“Drawing on her extensive private sector experience and her unrelenting commitment to excellence, she has led a broad range of initiatives to build a more open and inclusive institution, to overhaul our IT systems, and to change fundamentally how the Bank develops, manages and rewards its dedicated public servants.

“Along the way, she has inspired countless colleagues at the Bank and attracted a new cohort of professionals to it.”