National Highways is reminding road users that the M4 north of Bristol will be closed this weekend as part of the work on the A432 Badminton Road Bridge.

The M4 will be closed in both directions between junctions 18 and 19 from 7pm Friday, October 18 to 6am Monday, October 21 while a trench is dug under the motorway. This will allow utilities to be diverted that are currently within the bridge before the structure is demolished next year.

With 3,000 to 4,000 vehicles using this section of the M4 every hour over peak weekend periods the closure is likely to cause substantial disruption, and drivers are advised, where possible, to avoid the area and plan journeys for alternative times.

For motorists, a diversion westbound will be in place:

National Highways Route Manager Sean Walsh said: “This is one of the busiest sections of motorway in the South West which is why we are reminding drivers to plan their journeys during the closure.

“We carefully plan our schemes to limit any inconvenience, but sometimes it's not possible to carry out the work that's needed without a closure.

“Our message for anyone who plans to travel on the M4 around Bristol is to avoid the area if you can – if that's not possible, allow yourself plenty of extra time to complete your journey via our signed diversion routes and expect delays.”

Constructed in 1966, the Badminton Road bridge is a concrete post tensioned structure. In July 2023, a planned detailed structural investigation revealed accelerated deterioration and cracking to the southeast underside of the structure and the bridge was closed to traffic.

Having considered the options, demolishing and replacing the existing structure has been deemed the quickest and most economical approach.

The M4 closure has been carefully planned to happen while National Highways work on the A36 Warminster Road at Limpley Stoke has been paused to allow Wiltshire Council to undertake work on the A350.

Work on the bridge is set to complete in spring 2026.