The government has reiterated its commitment to public-private partnerships with the publication of a Treasury report that projects an extra £20bn investment in partnerships over the next three years.

The announcement comes in the same week as a report from the left-leaning Institute for Public Policy Research that criticises private finance schemes for failing to deliver greater savings.

It also follows contractors' fears that the government may abandon PPP for the refurbishment of London Underground.

Launched by chief secretary to the Treasury Andrew Smith, the report states that the government plans to expand its PPP programme, adding to the £12bn of deals already signed.

Smith said the investment would focus on health, education and transport and added that privately financed projects were delivering 17% savings in comparison with public sector alternatives. He said this represented a £2bn saving on a £12bn programme.