The Government's political gamble on improving the NHS could fail because of shortcomings in its huge investment and reform programme, according to a Downing Street advisor.

The warning has come from a leaked document sent to the Prime Minister and the health Secretary from Michael Barber, head of Number 10 delivery unit.

Last April, Chancellor Gordon Brown announced a rise in national insurance payments to pay for massively increased investment which will raise NHS spending to over £100 billion within five years.

The explicit link between the tax rise and promised improvements has put tremendous pressure on the Government and the NHS to deliver, but Mr Barber has warned that failure is a very real possibility.

The report, leaked to the Financial Times, says the most pressing task is to ensure PCTs make the best use of the resources now allocated to them, but says this is eing managed to a very tight timetable.

"We [the delivery unit] are concerned that there has not been enough forethought and planning [by the DoH] for this one off opportunity." It adds: "The risk is immense."

It identifies a number of "very significant challenges" including the eaknessof PCTs and the strategic health authorities who will performance manage them.

PCTs were given an unprecedented three-year budget allocations worth £148.3 billion in December, and are now commissioning services from NHS trusts to deliver better services, while simultaneously managing internal reform.

The new bodies were only established in April last year, and there remains a great deal of variation in the strength of local management teamsability to deliver on the Whitehall-devised performance targets.

The delivery unit believes the service can meet the targets set for this year including making sure no patient waits longer than 12 months for an in-patient admission. This is, however, just a half-way milestone towards bringing the maximum wait down to six months by 2005.

"Meeting the 2005 target will require a different approach which is not yet tested and substantial activity growth," the report suggests. It estimates a 15% increase in productivity is required, with an extra 900,000 patients on waiting lists seen every year. This will depend on a fundamental shift in how patients are seen, diagnosed and treated, and hinges on the ability of doctors, nurses and pharmacists to take on challenging new roles.

Potential pitfalls include the on-going negotiations over how to reward healthcare professionals for their new roles, with talks on consultant and GP contracts on a knife-edge.

The management style of the DoH is not spared from criticism, with concerns that many key posts are vacant, meaning it needs "to get the right people into the right jobs faster."

The programme aims to increase "choice and diversity" by greater involvement from the private sector is also identified as another area that needs to accelerate in order to deliver its promised improvements for patients.

pharmafocus@pharmafile.co.uk