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

The A43 – which links Oxford, Brackley and Northampton – provides access to Silverstone and connections between the M40 and M1. It was reopened on Sunday evening (19 July) 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.

The 50 mile 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.