Chancellor Philip Hammond has been urged to use caution in backing public infrastructure spending in next week's Autumn Statement.
Speculation is rife that Hammond will use his first fiscal event to announce new road and rail projects.
However, think tank Centre for Policy Studies warned that 90 per cent of large infrastructure projects are over budget, while the same is true of almost half of rail projects.
The policy wonks add that in China, where the highest proportion of GDP goes into infrastructure, over half of recent projects are seen to be destroying economic value.
But the CPS said the government could limit these risks by luring more private cash into broadband, airports, ports, energy industry, roads and social housing.
In particular, it backed new project, rather than infrastructure, bonds, which could be offered through the City to investors to back specific constructions.
These, it said, would also bring valuable private sector scrutiny.
“They could lead to significant improvements in the quality and efficiency of infrastructure projects,” the CPS said.