A confidential inquiry into allegations relating to waiting-list figures at South Warwickshire General Hospitals trust has led to the resignation of chief executive Andrew Riley, despite the fact that problems found were 'not serious' and no disciplinary action was planned.

Mr Riley, who was a member of the NHS Executive's millennium team, was suspended last October, following allegations about waiting-list irregularities arising from a regular internal audit.

Chair David Evans ordered an independent inquiry into the allegations, which was carried out by John Rostill, chief executive of Walsall Hospitals trust.

The report focused on management of waiting times related to non-urgent routine operations and was submitted to Mr Evans and trust non-executive directors.

Mr Evans said: 'After due consideration, Mr Riley has decided to resign from his position as chief executive to seek new opportunities elsewhere. The trust has restated the protocols involved in the recording of waiting lists and is confident that it complies with all requirements for waiting-list compilation. '

The report will not be made public because it 'contains confidential patient information which is clearly of a sensitive nature, as well as personal employment details'.

Trust non-executive director Reverend Justin Welby, who chairs the audit and finance committee for the trust, asked for external auditors to advise on trust procedures. He said: 'The external auditors' report said there was no particular cause for concern. '

Reverend Welby refused to discuss the contents, but said it had 'broadly confirmed that it was administrative problems', though its findings were 'not serious'. The nature of the findings could be judged by the fact that 'no disciplinary action is going to be taken'.

He declined to say why Mr Riley had resigned, but said: 'He is what is called the accountable officer, and therefore the guy who ultimately is responsible for what happens, and therefore he is the person who has to answer questions at the end of the day. ' He added that the chair and nonexecutive directors thought Mr Riley's resignation 'appropriate'.

Mr Riley would not comment on any aspect of the report and his resignation, and would not say if this was because of an agreement with the trust. He said: 'The only comment is that, having worked for the NHS for 25 years, I hope to remain working for the NHS. '

South Warwickshire community health council chief officer Janet Bonser said the trust had had a lot of increased admissions and was 'under pressure to meet targets'.