The Government is claiming £1.5bn in savings following its revamp of procurement for major infrastructure projects.
The Treasury said it is on course to strip-out £3bn of waste on construction costs by 2015.
The Infrastructure Cost Review has seen procurement streamlined.
Major savings include £600m on 20 major motorway improvement schemes and £400m on London Underground efficiency savings.
An accounting change has also seen t£700m slashed from the potential cost overrun buffer on the Thames sewer project.
The Treasury said the savings would be spent on extra infrastructure investment.
Lord Sassoon, Commercial Secretary to the Treasury, said: “What is particularly encouraging is that these savings are being delivered through close and fruitful co-operation between the public and private sectors.”