Unison members have voted to escalate strike action at Dudley Group of Hospitals trust in a dispute over a private finance initiative deal.Almost 600 mainly ancillary staff, who went on strike for 48 hours last week against transfer out of the NHS, have voted for seven-day strike action.

At a meeting between managers and Unison, the trust reiterated its position that the deal cannot be renegotiated. A further meeting was due with arbitration service ACAS on Tuesday.

The government changed the rules on PFI last June so that staff could be excluded from schemes. But the new rules do not apply to deals that went out to forma l tender before that date .

NHS head of private finance and capital Peter Coates wrote to the trust saying it would be 'impossible to sanction' retendering the project. But a spokesperson for Unison head office said: 'That doesn't stand up at all. We've got a dispute in Dudley - it doesn't necessarily mean renegotiating all PFI schemes.'