Labour delegates gave chief secretary to the Treasury Alan Milburn a rough ride at a fringe meeting on public finance.

Delegates said the private finance initiative was no longer needed because chancellor Gordon Brown has amassed a huge budget surplus.

It was alleged that Brown’s fiscal measures, if they continue in a similar vein for the next two years, will mean a budget surplus of more than £60bn. The angry delegates quizzed Milburn on why the government could not spend this money directly on new hospitals and schools.

Milburn backed the PFI process, saying that the private sector produced less waste than the public.

But he told delegates that civil servants were being trained to be more efficient and that more private sector help would be brought in to help spend money more efficiently in future.

Milburn also came under severe criticism for “selling off the family jewels”, in that health trusts do not automatically take ownership of hospitals at the end of the PFI period. But Milburn replied that, under new guidance: “There is a presumption at the end of the PFI period that the asset returns to the public sector.”

One critic of the current PFI guidelines recommended that NHS trusts be given more government money in order to broker better value deals with the private sector.

“A lot of assumptions about the efficiencies that are claimed by PFI consortia are wrong,” said the critic. “The trusts need an extra 5-15% funding to test these assumptions.”