National Highways will be embarking on a second phase of a major modernisation upgrade to the Saltash Tunnel this autumn.

The programme of work on the A38 tunnel which forms part of the strategic road network is described as a ‘generational’ refurbishment project and will cost £25 million.

The modernisation programme will see the upgrading of the tunnel and traffic control system within the 36-year-old tunnel and is expected to take 12 months to complete starting in late November.

From November until autumn 2025, Saltash Tunnel will be closed overnight, on week nights only, with drivers using the standard B3271 and North Road diversion routes during the 8pm-6am closure.

And between November and spring 2025, the inner westbound lane of the A38 will be narrowed between St Budeaux and the bridge roundabout, to enable working space for the installation of sign foundations.

From Spring 2025 until the scheme’s completion, the tunnel and bridge will not operate a tidal flow system. Instead there will be one fixed lane in each direction for A38 traffic, one lane dedicated to Saltash town and the eastbound cantilever open for local ‘tag only’ traffic. This will continue until the beginning of the summer holidays, says National Highways.

National Highways’ tunnel manager Julian Mitchell said: “The tunnel forms a key route between Plymouth and south east Cornwall, and any work has to be carefully planned with our Tamar Bridge partners and other stakeholders.

“Being a bi-directional tube with three lanes and tidal flow, and connecting directly to the Tamar Bridge, the tunnel is unique, and it’s difficult to work safely within the structure without closing it overnight.

“We appreciate the scheme will have some impact on road users and Saltash residents, but we’re keeping the closures to an absolute minimum.

“We’ll be keeping local communities informed ahead of the start of work. In the meantime, we advise people to plan ahead and consider a little extra time for their overnight journeys.

“We thank all drivers and residents in advance for their co-operation and patience ahead of starting work on this generational upgrade.”

Carrying around 40,000 vehicles a day, the 410-metre long, three-lane bi-directional tunnel is the tunnel in Europe operating a tidal flow system.

The current tunnel and lane control system is over 20 years old and approaching the end of its life. National Highways say the work will maintain safety within the tunnel, provide more reliable journeys and reduce the risk of unplanned closures.

Mr Mitchell adds: “The tunnel is safe but it is essential that we replace our systems which have been operating for 20-plus years, to make the tunnel fit for now and for the future.”