Somerset County Council

M5 Junction 25 highway improvements


SCC submitted an initial expression of interest (EOI) in mid-2014 to the Heart of the South West Local Transport Board (LTB). The LTB is empowered to oversee the management of transport schemes on behalf of the Local Enterprise Partnership.  The EOI was accepted as one of three schemes to be funded from a £35.4m Growth Deal funding allocation from Government to the Heart of the South West Local Enterprise Partnership in early 2015.

The Process
The LTB has set out a two stage business case process for schemes that have an allocation within a Growth Deal, this is similar to the Department for Transport’s major scheme bidding process but is slightly less onerous.

The first stage is to demonstrate value for money, deliverability and strategic case of the scheme. This allows the independent technical assessment team to provide guidance to the LTB around the acceptability of the scheme. This stage requires the promoter (SCC) to carry out analysis around the engineering feasibility, the economics, environmental and social impacts, the procurement options, the project management and community engagement.

The second stage business case requires the scheme to be virtually ready for delivery having secured planning permission (where necessary), carried out detailed design and engaged contractors through a robust procurement process. This second stage takes about 12 months to complete following approval of the first stage submission.

Progress to date
Since the acceptance of the EOI the first stage business case has been developed in line with LTB guidance and has been submitted for scrutiny by the independent technical assessment team. The team will review the evidence provided to support the scheme and will then present a report of their findings and a recommendation at the next Local Transport Board meeting (date to be confirmed). 

A358 Improvement
The M5 J25 has a close relationship with the A358 and the improvement that is currently being developed by Highways England (HE) therefore interaction with HE is an essential part of the M5 J25 project. They have confirmed that they will treat the SCC improvement scheme as already committed and will tie into it. SCC officers are attending HE workshops and have provided J25 scheme designs to HE for them to use in their optioneering.

As part of the M5 J25 business case the independent technical assessment team asked SCC to consider the impact of the HE improvement on the proposed scheme. It will be a number of months until HE’s preferred scheme is announced and therefore SCC tested the two most likely scenarios –

  • The improved A358 routes all traffic through M5 J25
  • The improved A358 provides new free flow links for traffic between M5 south (to / from Exeter direction) and A358 to avoid J25; all other traffic being routed through J25.

The purpose of these tests was to demonstrate that the improvement that the proposed SCC scheme will still offer value for money with any HE preferred scheme; by carrying out these tests SCC does not seek to set out any particular position nor pre-empt the work that HE has to do.

More details on Highways England’s work can be found on their website

Next Steps
Once the business case is approved by the LTB the next step will be to develop the scheme to a stage where it is detailed enough for SCC to apply for planning permission to build it. This will take some months and will include community engagement, detailed surveys of the area and technical design. In a parallel process SCC will need to start the procurement process in order to deliver the scheme within the funding window.

Consultation on the scheme took place in September and October 2016, the information that was provided at the consultation events can still be found at

The report of the consultation can be found in the Information and Resources area of this page.

Related services

Huntworth Roundabout improvements

Information and resources


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