Jeremy Corbyn has pledged to eradicate PFI deals from the NHS by using government money to buy them out.
The Labour leadership frontrunner said the private finance model championed by Tony Blair and Gordon Brown was a "mess" and was adding billions of pounds to costs.
"Labour has a duty to remove the PFI burden from the NHS - this really was our mess, and we have to clear it up," he said.
"PFI is like buying your house on a credit card. Patients are paying the price, with services and staff cut so that PFI debt repayments can be made."
Mr Corbyn highlighted figures from the Unite union suggesting that 15 NHS trusts were spending over 5% of their annual budget on PFI financing, and five were spending over 10%.