Care Quality Commission chair Dame Jo Williams has apologised for sharing personal information about the alleged mental health of a board colleague during her evidence to the health select committee yesterday.

During the regulator’s annual accountability hearing with the committee, Dame Jo, who announced her resignation last week, was asked about her actions in relation to non-executive director Kay Sheldon.

Ms Sheldon contacted the National Audit Office and gave evidence to the Mid Staffordshire Foundation Trust Public Inquiry as a whistleblower after becoming frustrated that her concerns about the regulator’s strategy and culture were not being listened to.

Dame Jo told MPs the board had been working together as a group to address these concerns and described it as a “huge shock” when the other members of the board had learned Ms Sheldon was going to appear at the inquiry.

She said: “There is a difference between raising a concern and expecting having raised it there is immediately going to be a solution. That was the difference between Kay Sheldon and the rest of the board.”

Pressed by MPs as to why she had written to then health secretary Andrew Lansley to request Ms Sheldon’s dismissal on the day she appeared at the inquiry Dame Jo said she felt there had been a breakdown of trust.

“There are processes and procedures that we have within the CQC that she did not choose to use. She could have gone to the secretary of state of a minister to express her concerns,” she said.

“It wasn’t that she shouldn’t and isn’t entitled to raise matters that concern her so deeply but she was working as part of a group and she chose not let us know [she was going to the inquiry].

Dame Jo said she had felt she had a duty of care towards Ms Sheldon - who has previously acknowledged that she has experienced mental health problems - and was genuinely concerned for her mental health.

She added: “I think I need to explain some of the issues that had happened around the autumn of last year. We were going through an exercise in late September which was about developing the board… Kay told us she was embarrassed and ashamed to be a member of the CQC board. Following that she left the meeting and was found to be in considerable distress.”

Dame Jo went into considerable detail about Ms Sheldon’s distress and shared details of comments she alleged Ms Sheldon had made about her mental state during a personal conversation.

A number of MPs called for Dame Jo to retract her comments and criticised her for making such personal comments about someone who was not there to answer them but she initially chose not to do so.

However at the close of the two and a half hour hearing Ms Williams apologised.

She said: “May I express my apology for straying into sharing information that I… regret.”

Ms Sheldon described Dame Jo’s account as a “gross misrepresentation of the facts” and said her treatment by the CQC as someone with a history of mental health problems had been “shameful”.

She disputed Dame Jo’s claim that the issues she had raised were already being dealt with, pointing out the board’s public response to her evidence to the inquiry had not acknowledged her concerns.