The Commission for Health Improvement's review of the West London breast screening service will send important messages to all NHS staff and trust boards (news, page 5, 19 April).

To establish confidence in the process, CHI needs to convince staff that such reviews are to improve systems for better quality patient care, and will never turn into expensive cosmetic and scapegoating exercises.

It is essential to give cast-iron assurances that there will be no victimisation of staff who contribute to such reviews and that anyone with relevant information will be allowed to meet CHI reviewers without a management 'minder'.

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 Department of Health's refusal to publish the Cameron report.

Human error of the type which appears to have happened in this case can never be completely eliminated, but the obvious first step in prevention must be to ensure a suitable working environment with open and collaborative management practices, and proper investigation of any staff concerns notified to personnel or occupational health.

As an ex-Hammersmith employee who has been cooperating constructively with the NHS Executive since 1998, I believe the new clinical director and the human resources director appear determined to implement the 'radical changes from the top down' recommended by Cameron.

They must now demonstrate that the whistleblowing policy not only claims but genuinely aims to protect and heed staff who raise concerns, whether to CHI or internally. With courage and determination to challenge unacceptable practices, the Hammersmith imaging department will eventually be able to recover its former good reputation. Positive and honest handling of the CHI review will help to achieve this.

Christine England ex-senior secretary in imaging and primary whistleblower 1995 and 1998 Milton Keynes