The £6.2bn National Programme for IT is supposed to overhaul the way medical records are kept, prescriptions issued and appointments booked by 2012.

But the London School of Hygiene and Tropical Medicine team said front-line workers felt disengaged, the British Medical Journal reported.

A programme spokeswoman said a major communications push was starting soon.

The upgrade is seen as essential to making the NHS more patient focused.

The new IT systems, which are being phased in over the next five years, will allow patients to book appointments at a hospital of their choice - from the end of this year they will be given the option of up to five - and allow them to pick up repeat prescriptions from any pharmacy in the country.

'Confusion'

NHS managers from four trusts told researchers there was so little consultation and communication from NPfIT officials that it posed a threat to the programme being successful.

After talking to 23 senior clinical and non-clinical staff at the end of last year the team concluded there was confusion about how the system would be implemented.

Some reported that local, existing IT systems for radiology and pathology urgently needed replacing, but upgrade work had been put on hold as implementation of the programme was phased in.

Dr Jane Hendy, one of the lead researchers, said: "Staff have shown a willingness to overcome the technical problems of getting NPfIT working, it's time the programme's headquarters engaged with managers and health professionals to implement this programme.

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"NPfIT success depends on it."

It is not the first time the programme's engagement of NHS staff has been questioned.

In January, a National Audit Office report said staff were not fully on board and choose and book - which will allow patients to book hospital appointments at a place, date and time of their convenience from GP surgeries - was behind schedule.

The IT upgrade will also allow electronic medical records to be stored for all patients, allowing patient details to be accessed anywhere in the country, but this has been dogged by claims that it will compromise patients confidentiality.

'Unrealistic'

And last year Computer Weekly magazine said the costs of the entire project could exceed £30bn.

Dr Richard Vautrey, the lead for IT on the British Medical Association's GPs committee, said while the situation had improved recently there was still "widespread cynicism" in the medical profession.

And he warned: "They have set a challenging timescale, it is probably unrealistic."

Gary Fereday, policy manager for the NHS Confederation, which represents health service managers, said he recognised the points being made in the BMJ study.

But he added: "It's a complicated issue and I think some levels of doubt from clinical staff was always anticipated.

"The important thing now is looking at how to overcome these hurdles."

A spokeswoman for the programme said officials were working with GPs, hospital doctors, nurses and allied health professionals to "develop understanding of what benefits" the project will bring.

And she said: "The paper pre-empts a major communications campaign due to commence in September 2005.

"This will inform and educate both NHS staff and the public about the changes and benefits that the new technologies will bring."