The B4069 at Lyneham Banks in Wiltshire, dubbed England’s “wonkiest road”, has reopened to traffic following extensive remediation works to damage caused by a significant 2022 landslip.
The road, which serves as a vital link for the local community and once accommodated over 5,500 vehicles daily, was closed following the landslip that displaced around 90m of the carriageway, shifting it 40m down the hillside.
The landslip was attributed to several factors, including historical ground weaknesses, increased groundwater flow and additional pressure from nearby development. In fact, the B4069 earned its reputation as England’s “wonkiest road” due to its geological challenges and the council’s local highways inspector had reported subsidence on the road over a year before the landslip.
Following the February 2022 incident, Wiltshire Council had to wait several months until the road stopped moving before it could establish the cause of the landslip and assess the best way to rebuild the road to prevent the landslip reoccurring. Once that was work was completed, the council drew up detailed plans on several options to repair the road before engaging with stakeholders and appointing a contractor, Octavius Infrastructure, which started the repairs work in July 2024.
Work to reinstate the road started in July 2024
Octavius completed the project on schedule and within its £5M budget. The reopening ends lengthy detours for drivers and reconnects local communities previously split by the road’s closure.
To address these issues and prevent future incidents, the project included the construction of a 108m-long contiguous bored pile retaining wall, built alongside the westbound carriageway. This wall consists of 120 reinforced concrete piles, topped with a capping beam of 1.5m in height.
In addition to the retaining wall, extensive drainage systems were installed both beneath the new carriageway and on the hillside above and below to manage water flow and reduce the risk of further subsidence.
However, the poor ground conditions presented challenges during the project, preventing crews from replacing unstable soil—a method deemed ideal. Instead, engineers had to compact the ground in a more time-consuming manner, working in nine separate 10m sections along the carriageway.
The project was completed on time and on budget
Throughout the project, buried obstructions complicated the excavation process, often requiring deeper digs to ensure the stability of the piling work. The fragmented drainage installation mirrored these challenges. Initial drains helped to dry out the ground, allowing teams to return to areas and complete the full drainage system. Limited access to the site, due to its rural B road status, further constrained the pace and number of concurrent operations that could be performed.
The successful reopening of the B4069 not only restores an important transport route but also exemplifies the complexities involved in civil engineering projects that must contend with challenging geological conditions. As the local community rejoices in the restoration of their road, it serves as a reminder of the delicate balance between infrastructure and the natural environment.
Key facts about the project
Octavius highways operations director Chris Hudson said: “This was a challenge. About 90m of carriageway was lost. The hillside was still creeping when we commenced work, tackling such ground conditions demanded some creative solutions. But we are about bringing people together, so it was great to help reconnect communities affected by this lengthy road closure.”
Wiltshire Council corporate director place Parvis Khansari said: "We’re delighted that the B4069 Lyneham Banks has finally reopened after several years of hard work to both restore the road and introduce measures to prevent the land from slipping again.
“The closure has had a real effect on the local community and we thank them for their patience and understanding during the work.
“I’d also like to thank our officers and the team from Octavius Infrastructure, who have worked hard to deliver this project on time and on budget.
“This reopening marks a significant milestone, ensuring safer and more reliable journeys for all who use the road.”
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