Every inquiry is different. But classic ingredients appear to include at least one whistleblower, a culture of secrecy, and previous internal inquiries which have failed to bring about sufficient action.

By the time the Commission for Health Improvement launched its investigations into North Lakeland Healthcare trust and Carmarthenshire trust in Wales, internal inquiries were already under way.

CHI believes the bulk of its investigations will follow a similar route.

Yesterday was due to be Oxford Radcliffe Hospital trust's turn in the spotlight - as the findings of an external review of its cardiac services were launched by South East regional office.

The report into cardiac services was due to assess the way the trust 'responds to concerns of senior nursing and other staff in cardiac services', as well as the 'way cardiac services are provided at the trust'.

That regional review followed the suspension of consultant cardiothoracic surgeon Ravi Pillai last December, after Colette O'Keefe, senior nurse manager of the cardiothoracic unit, made five claims against him.

A preliminary internal investigation cleared Mr Pillai of three of the claims - including those criticising his drinking and patient care - and he returned to work in February 'without any restriction in his clinical practice'.

But in an internal memorandum seen by HSJ, director of personnel and administration Mike Fleming said the 'investigation also concluded that two of the allegations may have substance'.

These are understood to concern relations between Mr Pillai and staff at the unit.Ms O'Keefe has been on sick leave ever since.

Speaking on Tuesday, a spokesperson for the trust said the investigations which followed it were 'still in process'and hoped to conclude by the time the regional review was issued the following day.

But HSJ sources are concerned that the limited remit of the review - which does not include patient care or complaints - could mean it is unable to grapple with some of the most difficult issues.

HSJ understands that evidence from Ms O'Keefe to the regional review, run by Jules Dussek, president of the Society of Cardiothoracic Surgeons, Stephen Bridge, chief executive at Papworth Hospital trust, and Wilma MacPherson, director of nursing at Guy's and St Thomas'trust, suggests that concerns about patient care date back several years.

Oxfordshire community health council has been involved in four serious clinical complaints against the hospital since 1996 and is aware of five others. CHCs further afield were involved with two of the most high-profile cases for which Mr Pillai was responsible, including the deaths of Safeena Begun, aged two, and that of Irene Godfrey,66, who had a swab left inside her body.

And Oxfordshire CHC has 'had significant concerns about the cardiac unit at the John Radcliffe Hospital since 1998'.

Chief officer Linda Watson says: 'The prime issue for us is that of patient safety and patient care. We have found it difficult to get answers to questions that we have put to the trust and therefore welcomed the external review.

'We and members of the public will expect to see the recommendations of the review panel will make a difference, and that where things have gone wrong, someone will be called to account.'

South East regional office refused to discuss any of the issues discussed in the regional review ahead of publication.

Mr Pillai was unavailable for comment.

The trust is one of Britain's most high-profile NHS centres and has attracted some of the NHS's most well-known names. NHS chief executive Nigel Crisp was at the John Radcliffe's helm from 1993 to 1997.

John MacDonald, who replaced him, moved on to Queen's Medical Centre Nottingham trust last year.

Since April, David Highton, previously chief executive of Chelsea and Westminster Healthcare trust, has been the Radcliffe's chief executive.

Dr Chris Bunch, chair-elect of the British Association of Medical Managers, was the trust's medical director for 13 years - until he resigned in September.

The timing of the report's release - it was due out in the summer - is especially intriguing. HSJ sources had already speculated that 'high-level anxiety'about its sensitive nature meant it was likely to come out on a day when it might be overshadowed by other news stories.

The release of the review findings on the same day that CHI launched its first two investigation reports did little to wipe away that cynicism.