Plans to computerise the NHS in England could face further delays after a contract with a key supplier was terminated, the BBC has learned.
The IT programme, which is already four years late, will create a single electronic records system for patients.
But negotiations have broken down with Fujitsu, who had been due to implement the plan in the south of England.
The Department of Health said an agreement over Fujitsu's contract could not be reached.
The estimated final overall cost of computerising the NHS in England is currently £12.7bn.
Financial penalties
While the NHS's Connecting for Health programme has overrun, tough contracts have so far kept it broadly within budget.
However, these have caused tensions with the companies tasked with carrying out the work.
As the programme has developed, contracts have been renegotiated to include strict local specifications.
They state that contractors will only be paid when services are delivered and working.
If deadlines are missed, payment is deducted, although it can be earned back.
Fujitsu was one of three main suppliers of the system and had held a contract worth £895m for the south of England from Kent to Cornwall.
Fujitsu withdrawal
But now its involvement has ended after the parties failed to agree on the specifics of its contract.
The DoH told the BBC it terminated Fujitsu's involvement "with regret" because it had not been possible to reach agreement.
In a statement, Fujitsu said it had withdrawn from negotiations as it did not feel there was any prospect of an acceptable conclusion.
Existing computer programs installed by Fujitsu in the south of England will continue to be supported, but what happens to those not yet up and running may now be the subject of a legal dispute.
A recent National Audit Office report said an unspecified amount had been withheld from the Fujitsu contract.
The NHS IT programme was launched in 2002 and had been due to be completed in 2010.
The Conservative shadow health minister Stephen O'Brien said the government's attempts to "ram through a top-down, centralised, one-size-fits-all central NHS computer system" had come "crashing down around their ears".