Calls to make the Commission for Health Improvement an independent body were bolstered this week as it emerged that the Department of Health may refuse to hand over confidential evidence requested by CHI.
CHI is currently conducting an investigation into the breastscreening service run by Hammersmith Hospitals trust. As part of that investigation it had requested access to a report undertaken for the DoH by the University of Wales College of Medicine's vice-chancellor, Professor Ian Cameron.
The findings of the report, an investigation into the trust's imaging directorate which runs the screening service, were never made public. CHI requested the report, as part of its background material, three weeks ago, but ministers were still deciding whether to releaseit as HSJ went to press.
The investigation is the first which CHI had undertaken without a request from the health secretary. It was called for by then trust chief executive John Cooper, now retired.
Although CHI can demand that service providers, such as trusts, hand over relevant information, its remit gives it no power to ask the same from external organisations such as the DoH or royal colleges.
It is understood this is the first time a request has been held up.
Whether or not the report is passed on, any delay could prove politically embarrassing, and add weight to the recommendation in the Kennedy report on Bristol Royal Infirmary to make CHI independent of the DoH and report directly to Parliament.
At the time the inquiry started, a letter published in HSJ from a former employee in the service raised the issue of access to material.
Christine England wrote: 'As the unit currently under review is part of the Hammersmith imaging department, CHI should also have access to anonymised evidence given to last year's Cameron inquiry, despite the DoH's refusal to publish the Cameron report.'
But a DoH spokesperson said: 'Each individual request for information is considered on its merit.
As the Cameron report was a confidential report to ministers, it is the normal process for ministers to be involved in discussions concerning its release.' Even if the report is passed on to CHI, its findings will remain confidential.
Birmingham University's health services management centre senior research fellow Dr Kieran Walshe said: 'It could be politically very embarrassing for the DoH to refuse a document to its own watchdog.
'This is, perhaps, a really interesting test of CHI's ability to be independent of the deparment. Everyone knows the Kennedy report [into the Bristol heart babies deaths] said CHI should be independent of the department.'
Radiologist Professor Peter Dawson, who resigned from the trust in 1999 after raising concerns about safety and standards of work, said: 'This is obviously a test of CHI's independence and of the sincerity of the Department of Health's rhetoric to create a new culture.'
The CHI investigation continues as breast-screening remains suspended because of a failure to provide an adequate service.
It has already been suspended for nearly five months, with no immediate prospect of restarting as new staff are still being recruited.
The unit would normally expect to screen around 8,000 women in a five-month period and to detect around 60 cancers.