The £1bn project will create a new 10-mile dual carriageway between the A1 Black Cat roundabout in Bedfordshire and A428 Caxton Gibbet roundabout in Cambridgeshire.
The scheme is expected to open to traffic in spring 2027 and cut journey times by a third in rush hours.
Local dignitaries were on hand for an official ground breaking ceremony on Tuesday 12th December 2023.
Project director Lee Galloway said: “Today marks a pivotal milestone for everyone connected with this much-needed and wanted scheme. To get to this point would not have been possible without the dedication of our team, the support of our partners and stakeholders and the invaluable input from local communities.
“This project is about connecting communities and leaving a positive legacy in the region. Throughout construction, we are committed to bringing the community on the journey with us, minimising disruption and ensuring that local people and businesses remain an integral part of the process.”
In March 2021, when Skanska was awarded the contract, the cost was put at £507m. With delays caused by legal challenges, inflation that has increased to £679m and total project costs to £1bn.