A top left-wing think-tank today criticised Tony Blair's plans for increased public-private partnerships.

The Institute for Public Policy Research said the private sector has a chequered history in delivering public health and education projects.

Its Commission on Public Private Partnerships concluded that while PPPs have achieved significant savings on roads and prisons projects, there is no evidence of success in school and hospitals.

The think-tank supported Tony Blair's view that there should be "no ideological barriers" to using PPPs but said fundamental reforms were needed to improve public services.

The report was published as some Labour MPs and unions expressed alarm over the extent of the plans.

Transport and General Workers' Union general secretary Bill Morris said: "The British people want their public services delivered by a robust, and well-resourced public sector.

"The T& G supports that view.

"We believe public services have a social worth well beyond profit margins and we say that any public sector reforms should be based on the principle of public ownership and accountability."

David Hinchcliffe is the Labour MP for Wakefield who chaired the health select committee during the last Parliament.

He said: "I feel that within the Parliamentary Labour Party, there would be tremendous opposition to any moves in terms of increasing the existing role of the private sector in the National Health Service."