Tony Blair's five-year NHS plan will offer a huge business opportunity for a US healthcare corporation with close personal links to Downing Street, it emerged yesterday.

The plan includes a pledge that every primary care trust in England will adopt the approach to caring for vulnerable older people now being pioneered by the United Health group, a $28bn corporation based in Minneapolis.

Last month the company recruited Simon Stevens, currently the prime minister's senior health policy adviser, to become its vice-president with a brief to expand its European business.

Mr Stevens was regarded as the most influential voice in the development of health policy. He crafted the NHS plan in 2000 while working as an adviser to Alan Milburn, then the health secretary, and was the brains behind most subsequent developments, including solving the NHS waiting list problem by contracting out work to foreign firms.

He left Downing Street four weeks ago and will take up his new post later this year. He has made clear that he will not use his position of influence at the heart of government to help his new employers.

The five-year plan published by John Reid, the health secretary, was regarded within government as one of the most important policy pronouncements in shaping the political debate in the run-up to the next election. In paragraph 3.16 it said: "Nine PCTs [primary care trusts] are working to adapt and implement case management for vulnerable, older people. Strategic health authorities are now developing case management approached across their health communities for implementation by April 2005.

"This model of care will be adopted by every PCT between 2005 and 2008, by which time there will be over 3,000 community matrons using case management techniques to care for around 250,000 patients with complex needs." A Department of Health spokesman confirmed that the nine PCTs referred to trusts piloting "Evercare", a programme designed by United Health group to keep older people out of hospital by providing them with care in their own homes. The department has paid £5m towards an 18-month experiment in the nine areas, of which £3.7m will go to United Health and the rest to recruiting extra NHS staff.

The spokesman was asked whether the commitment to introduce this approach throughout England was a "licence to print money" for the company soon to joined by the prime minister's former adviser. He said: "We have set out the key principles of good chronic disease management ... it will be for local commissioners to determine how best to assess and meet the needs of their health communities. The Evercare approach is one example of case management. Other work is going on -- for example, Castlefields Health Centre, in Runcorn, was recently praised by the Audit Commission for its case management of the at-risk elderly. There will be oppportunities for lots of different organisations to contribute to the roll-out, but all decisions will be made locally."

A Downing Street spokeswoman said: "The idea that this indicates any kind of impropriety is nonsense. The fact is that PCTs can choose a range of providers to deliver this kind of patient analysis and also have [the] flexibility to deliver services themselves. It is an open market place and PCTs are free to choose..." A company source indicated, however, that United Health had been talking to strategic health authorities about signing up groups of PCTs en bloc to adopt its approach to NHS problems. In the US it claims to have cut hospital admissions by 50% and made patients and carers more satisfied.

Lois Quam, a senior executive at United Health, said: "The group is supporting the NHS by providing innovative solutions that improve patient care." An interim report on the UK examples of the Evercare programme in nine PCTS highlighted the scheme's success, she said.