Prime Minister Gordon Brown pledged on Monday to put patients at the heart of the National Health Service, seeking a tonic for his flagging ratings as the state-funded system prepares to mark its 60th anniversary.

"If the challenge 10 years ago was capacity, the challenge today is to drive improvements in the quality of care," Brown said in the foreward to a review of the cradle-to-grave health programme in England being published later.

"We need a more personalised NHS, responsive to each of us as individuals, focused on prevention, better equipped to keep us healthy and capable of giving us real control and real choices over our care and our lives."

The year-long study by Health Minister Lord Darzi will be unveiled together with a draft NHS constitution, setting out patients' entitlements to healthcare.

The review is expected to focus on how the quality of care can be improved, while the constitution will detail what patients can do if their needs are not met.

Brown, facing a slump in his personal ratings and polls predicting defeat in the next election due by May 2010, promised a "bold vision" for the NHS, which employs 1.3 million people in England and will spend more than 100 billion pounds next year.

The review is expected to call for the devolvement of more services out of the massive health provider to cut bureaucracy and speed up improvements in care.

"It requires government to be serious about reform, committed to trusting front-line staff and ready to invest in new services and new ways of delivering services," said Brown.

Unions fear the plans will mean privatisation of the state health system by the back door, with private companies invited to bid to run services such as local clinics.

Leading surgeon Darzi is expected to promise more autonomy to clinicians and regional health authorities, with fewer top-down targets from Whitehall in areas such as reducing waiting lists.

Patients will be offered more choice over how and where they receive treatment, and greater information on the success of treatments at individual hospitals.

Darzi has already published separate reviews for England's strategic health authorities and Monday's report builds on these.

Plans to build a network of 150 supersized surgeries - or polyclinics - are already underway, offering patients access to a team of family doctors and nurses seven days a week.

The polyclinics are a key part of Darzi's plan to widen access to healthcare but have run into stiff opposition from the British Medical Association, who fears they spell the end of small family doctor practices.