The project is now expected to be complete in 2026 following a design error related to the rollout of the bridge over the River Witham and the East Coast Main Line.
Upon learning about the issue, Lincolnshire Country Council demanded a solution and is seeking to recoup the additional costs.
Cllr Richard Davies, executive member for highways, said: “The complexities of designing and constructing this relief road, particularly this bridge, are far beyond what we as a council can do directly.
"That’s why top international engineering companies and experienced contractors were entrusted to handle the project. Although we oversee the scheme as a whole, we rely on our suppliers’ combined expertise.
“When undertaking a project of the magnitude, all design work also undergoes a mandatory, additional layer of independent checking. Unfortunately, despite all of this, a mistake was made along the way that’s led to this new delay.
“This mistake related to the how the bridge was to be installed and us being told it couldn’t be pushed into place as intended due to concerns relating to specific wind conditions.
"Safety comes first, so the work was halted so our designers and contractors could address the problem.
“We’ve done everything you could reasonably expect us to do as the client for the scheme, but we feel we’ve been let down.
“The important thing is that the details of the solution are nearly finalised, meaning we can start pushing the bridge into place in the coming months.”
The impacts
The relief road is now expected to open in 2026, a year later than expected. Rectifying this issue is expected to cost between £10-20 million, bringing the project’s expected total to £158-168 million.
Cllr Davies said: “Let me be 100% clear: while we may need to cover these extra costs initially, we will ensure that those responsible for this are held accountable and that every penny of taxpayer money will be recovered.
“We are pursuing contractual and legal processes as a result of this error so are unable to comment any further on this at this stage for legal reasons.
"For now, our priority now is getting this massive project back on track as soon as possible – and that means continuing to work closely with our appointed contractor and designers.”
What’s next
Once underway, the bridge push over the 293-meter span will take several months as it crosses the rail line during overnight periods when trains have stopped running.
The rest of the structure will then be built on the east side of site, including lifting new steel beams into place.
Several more months will then be spent concreting the decks, installing safety barriers, and laying road surfacing.
Cllr Davies ended: “While this new delay is incredibly disappointing, we remain 100% committed to completing Grantham’s relief road.
“As a local resident and business owner, I understand and share the frustration this delay will cause. But safety comes first, and even the smallest risk must be taken extremely seriously.
“In the meantime, I want to thank everyone for their continued patience as we work towards completing this monumental project.”
For the latest news on the Grantham Southern Relief Road, visit www.lincolnshire.gov.uk/majorprojects.