HS2 completes major A43 works during twin weekend closures

The construction of a bridge that will allow high speed trains to pass under the busy A43 near Brackley took a major step forward over the weekend with completion of a complex multi-stage realignment of the dual carriageway. 

The A43 – which links Oxford, Brackley and Northampton – is a vital route, providing access to Silverstone and connections between the M40 and M1. It was reopened on Sunday evening after two consecutive weekend closures. 

Preparatory work began in 2023 when HS2 engineers, working closely with National Highways, realigned the road to create an ‘island’ between the two carriageways big enough for the construction of the new bridge. 

Using a ‘top-down’ approach, they sank 52m deep piled foundations and then built the pile caps and piers that support the 66-metre-long bridge deck that carries the road. Seven huge steel beams were then lifted into place to support the concrete deck. 

With the road surface complete, the team used the last two weekends to close each direction of the road in turn and divert them across the new bridge - while the other one stayed open. With traffic now flowing in both directions, excavation can begin to create space for the railway to pass underneath.  

This multi-stage approach was designed to keep traffic flowing and disruption to a minimum. The final closures were also delayed to avoid the F1 British Grand Prix, which was held at Silverstone at the beginning of July 2026. 

HS2 Ltd’s Head of Delivery Luis Gonzalez said: 

"The A43 is a busy route between Brackley and Northampton and I’d like to thank drivers for their patience over the last two weekends, while we safely realigned the road over the new bridge. 

“With the traffic flowing over the top, we can focus on the next part of this complex multi-stage project – excavating the cutting that will take the railway under the road.” 

The 50 mile (80km) stretch of railway that passes Brackley – including the A43 bridge – is being delivered by HS2’s main works contractor EKFB, a team made up of Eiffage, Kier, Ferrovial Construction and BAM Nuttall working with ASC (a joint venture between Arcadis, Setec and COWI). 

They worked with National Highways and EKFB’s sub-contractor, Kier Transportation, to construct the temporary realignment so that traffic could keep flowing during the construction of the bridge.

Significant progress has also been made with some of the smaller roads and bridges across Buckinghamshire and Northamptonshire, with six reopened to local traffic in the last six months.   

These includes the A4421 Buckingham Road, Edgcott Road, near Quainton, and Oatleys Road, which crosses the Turweston green bridge, near Brackley. 

EKFB’s Project Director, Tony Wehby, said:  

“Completing the construction works on the A43 marks a significant milestone for the EKFB team and its supply chain partners. This completion now allows us to the remove material from underneath the road and press ahead with our earthworks programme in this area.  

“Thank you to EKFB’s highways and traffic teams, National Highways, Kier Transportation and the construction team for the world-class operation, not only on the opening on the A43 but also the opening of six other roads around the Brackley area. Not only have we limited the disruption for our local communities and road users, but we have done so in a considerate and safe way.” 

National Highways Head of Network Planning and Development, Ian Doust, said:  

An infrastructure project on this scale will inevitably cause some disruption but our priority is reducing the impact on the people who use our roads as much as possible. 

“Thanks to some innovative traffic management, cutting edge engineering and close collaboration between National Highways, HS2 and their partners, we have been able to do that. 

“It is very satisfying to see the traffic now flowing in both directions on the new bridge and the progress being made on this complex project.”  

In total there are more than 500 bridging structures on the HS2 project. These range from small footbridges and culverts, to innovative ‘green bridges’ designed to help wildlife cross the railway, massive motorway crossings and the record-breaking Colne Valley viaduct.  

The new high-speed railway is designed to improve connections between London, Birmingham and the North while freeing up space for more local trains on the most congested southern end of the existing West Coast Main Line into London Euston. 

However, there is still significant work to do across the whole 140 miles between London and Birmingham. Mark Wild, HS2 Ltd Chief Executive, is now leading a comprehensive reset of the project to ensure the remainder of the route is delivered as efficiently as possible and for the lowest reasonable cost.