Dunno, but the article implies that this was some sort of 'switch point' in the deal - maybe the actual cost of the hospital build had been recouped by the PFI company and the trust had a clause allowing them to opt out of the purely maintenance part of the contract as long as they paid the PFI company a set amount as compensation.
You'd assume the PFI company would be happy to accept that - they'd get their profit up front rather than having to wait for it. Especially given the fact the PCTs are all going to be dissolved soon, they might have been left with a PFI contract with a PCT that didn't exist any more and who knows if whatever replaces the PCTs would be willing to stick to the PFI contract at all..
(God, public finances really are three letter acronym hell..)
Jon