The Commission for Health Improvement has confirmed that it has no powers to require one of its own commissioners to provide it with information relating to one of its investigations, it emerged last week.

CHI is conducting an investigation into the breast-screening service run by Hammersmith Hospitals trust, as part of which it had requested a copy of a confidential Department of Health report compiled by Professor Ian Cameron. The report had not been provided six weeks after the request from CHI, and questions have now been raised about whether CHI could obtain the information from the report's author, who is a commissioner.

Professor Cameron, who retired as vice-chancellor of the University of Wales College of Medicine this year, sits on the investigations and fast-track review programme board for CHI. His report to the DoH last year covered concerns about patient safety and staffing problems in the imaging directorate at the trust, which includes the screening unit. Professor Cameron is not involved in the investigation because of his connection with the trust report.

CHI has confirmed that, if the report is not handed over, it could ask Professor Cameron to speak to it about the contents but could not compel one of its commissioners to provide information.

CHI director of communications Matt Tee said: 'If it decides not to [release the report], we would seriously think about asking him for an interview.'

Mr Tee said that, in the event that a commissioner refused to co-operate, it would be up to the DoH to determine whether CHI needed extra powers to enable it to compel individuals to provide information.

Whether the DoH, which refused to release the report in the first place, would want to grant extra powers to allow CHI to find out about its contents is open to speculation.