Major Milestone Reached on M3 Junction 9 Upgrade as Steel Beams Installed

A key stage has been reached on the M3 Junction 9 improvement scheme, with National Highways preparing to install steel beams for the new roundabout structure.

To allow the work to be carried out safely, the M3 will be closed in both directions between junctions 8 and 9 from 9pm on Friday 30 January until 6am on Monday 2 February. A second full weekend closure is planned from 13 to 16 February, when further beams will be lifted into position on the southern side of the junction.

The first phase will see steel beams installed on the northern side of Junction 9, followed by the placement of 40-metre-long beams weighing around 100 tonnes during the second closure.

Tom Beasley, Senior Project Manager at National Highways, said the junction plays a vital role in the regional and national economy.

“This interchange is critical for economic growth, linking the ports of Southampton and Portsmouth with the wider motorway network and supporting the movement of millions of tonnes of freight,” he said.“It is also a key route for people travelling to and from the south coast for work and leisure.

“Reconfiguring the roundabout is essential to improving these connections, and the installation of the first bridge beams represents a significant milestone for the project. To carry out this work safely, motorway closures are unavoidable, and we encourage drivers to plan ahead and allow extra time for their journeys.”

The Junction 9 upgrade is designed to support the delivery of around 2,000 new homes in the Winchester area while improving journey reliability. Once complete, peak-time journeys through the junction to the A272 are expected to be nearly 30 per cent quicker.

Drivers travelling between the M3 and the A34 are also forecast to see peak-hour journey time reductions of more than 20 per cent.

Following the beam installation, work on the new roundabout will continue over the coming months, with the upgraded junction scheduled to open fully to traffic in summer 2028.

The redesigned roundabout will enable the M3 to be widened and allow for dedicated A34 connections, improving freight movements from the south coast ports to the Midlands and beyond.

The scheme also includes environmental enhancements, such as the creation of more than 22 acres of chalk grassland, along with new routes for pedestrians, cyclists, and horse riders.