The report by the Oxford-Cambridge Supercluster Board, external has urged Chancellor Rachel Reeves to move more quickly to propel growth in the so-called “high-tech corridor” by speeding up the building of infrastructure and homes.
The board is backed by 46 organisations including universities, listed companies, and global investors such as AstraZeneca, GSK, Airbus, the Ellison Institute of Technology, Aveva, Bidwells, Leonardo, Silverstone and Darktrace.
Starting construction in this five-year Parliament would provide the certainty investors needed, said the report.
Firms are worried it will take 18 months for the DCO to be approved.
They have called on the government to fast-track the examination and decision phase and provide clear timelines to ensure construction begins sooner.
The Oxford-Cambridge Supercluster Board previously said the region could add billions of pounds to the economy.