Shares in medical software group iSoft - which has its main UK office in Birmingham - plunged 40 per cent yesterday after it warned delays to the project to put patient data on to a central NHS computer would wipe £45 million off its profits.
ISoft said it was clear that much of its software would not be delivered to NHS Trusts on schedule and its revenues from the programme would be £55 million below hopes for this year at £30 million.
Shares in the firm, which received a major boost in 2004 when it was picked for a multi-billion-pound project to upgrade systems for the NHS Service, plummeted to 216.75p, wiping more than £320 million off its market value.
NHS chief executive Sir Nigel Crisp said at the start of November that parts of the £6.2 billion IT programme were running a year behind the original timetable.
ISoft was chosen to put software into NHS trusts in the North-west, North-east and the East of England - three of the five regions to be part of the scheme.
Analysts who had looked for £295 million revenues for the year to April scaled back their estimates to £240 million, but iSoft insisted the issue was one of timing and revenues over the whole life of the programme should be unchanged.
Chief executive Tim Whiston said: "It's simply the fact that, with the passage of time, we now have identified there is risk that the rescheduling of the process won't be completed this (financial) year."
In its statement, iSoft said it was unlikely to generate as much cash as previously thought this year, although flows would be positive.
ISoft added: "The potential impact on future periods will only become clear following the completion of the rescheduling process which is expected to take place over the coming months. In the meantime, the company is not assuming a significant near-term increase in annual revenues from the programme."
A central computer system is seen as vital to the NHS to cut out the potential for errors as doctors treat patients for the first time and boost efficiency.
The programme was scheduled to last ten years and connect more than 30,000 GPs in England to almost 300 hospitals and give patients access to their personal health and care information, transforming the way the NHS works.
Despite the setback with its NHS contract, iSoft confirmed trading elsewhere in the firm was in line with expectations.