Planning Inspectorate publishes A358 dualling scoping report

Highways England intends to dual the A358 between the Southfields roundabout near Ilminster and Junction 25 of the M5 at Taunton, as part of a wider programme of road improvements across the south west.

The agency intends to hold further public consultation on the proposals for the dualling later in the year, before a formal application is submitted to the Planning Inspectorate.

The inspectorate has now published its initial opinion on the proposals as they currently standing – known technically as a scoping report.

Here’s what we learned from reading the inspector’s report…

• It may not be finished until 2028: the construction will be split into two phases, with phase one covering the section between the M5 and the A378 to Curry Rivel, and phase two from the A378 to the A303. Highways England anticipates that “it would take 44 months to construct the Proposed Development and that it would open to traffic in 2028, subject to review”
• A new construction compound may be built near the A378: HE is currently considering sites for the construction compound, where staff, vehicles can be accommodated. While the location has not been confirmed, the agency says the main compound is “anticipated to be located at Mattock’s Tree Green” near the A378 junction, with a smaller satellite compound near Ashill
• We can expect plenty of disruption at weekends and bank holidays: the A358, like the A303, is an essential arterial route for holidaymakers wishing to visit or stay in the south west. Nevertheless, HE has admitted that “limited temporary road closures along the existing A358 may be required at night, weekends and bank holidays, together with other temporary traffic management measures, including lane closures and contraflows”
• Numerous new bridges will be needed: while the new route does follow the footprint of the existing A358 for much of its length, new structures will need to be created to support both the widened section and the new carriageway which will bypass Henlade. To this end, the scheme will include “five new road over-bridges, one road under-bridge, and seven watercourse structures”, as well as changes to 25 local roads and a number of rights of way being diverted or “permanently stopped up”
• A river may have to be diverted: the report contains a brief mention of Highways England’s plans for “the proposed permanent diversion of the River Ding”, which runs under the A358 near the village of Horton. Details of how this will be achieved, or the impact this will have on the local environment and residents, are very scarce – but this may change with the new public consultations
• The dualling will have a “limited” impact on the Blackdown Hills: the Blackdown Hills area of outstanding natural beauty (AONB) lies to the west of the A358, straddling the border between Somerset and Devon. The report argues the dualling would not adversely impact the AONB’s character since they only have a “limited visual relationship” with the existing route and the new section will not cross into the protected area
• The Southfields roundabout would only see “minor changes” to its layout: where the dualled road joins the A303, there would be “minor changes” to its layout, including the widening of the carriageway and the entry arms at the various junctions, including the eastbound exit on the Ilminster bypass. Very little work would be needed to alter the recently created Nexus roundabout at the Taunton end. 

Residents of Ashill, one of many small villages along the current A358, have criticised the new road’s designs, arguing they do not take account of existing issues and housing growth.

Parish council chairman Peter Lang said: “Throughout their planning processes, you have not given any consideration to the safety or the well-being of all who live in Ashill, or to the residents of surrounding villages also living along the A358.

“It would be a sad day if it all went wrong and lives were lost.”

Linda Vijeh – the district councillor for Neroche and the county councillor for Ilminster – raised a similar issue in a recent email newsletter to her constituents.

She said: “Concerns have been raised to me over the volume and speed of through traffic using Windmill Hill Lane in Ashill as a short cut, instead of Wood Road and the old A358.

“Given recent planning permissions (to which the community were strongly opposed), it is felt that this issue will increase with the building of new developments in the area and plans for the dualling of the A358 progress.”

HE is expected to confirm dates for the next round of public consultation in the coming weeks, with a full application being submitted to the Planning Inspectorate later in the year.