WORK to modernise the Saltash Tunnel has entered a crucial stage, with National Highways confirming that the main phase of the technology upgrade is now underway.

The £25-million project aims to bring the 37-year-old tunnel up to modern safety and efficiency standards, marking the most significant refurbishment in its history.

The tunnel, which links Cornwall and Devon via the Tamar Bridge, has been undergoing an extensive Tunnel and Traffic Control System upgrade since January. The first phase, which involved major civil engineering works and the installation of new gantries, was completed in late summer.

In total, the scheme will see 31 miles of new cabling installed in and around the 410-metre-long tunnel. So far, 70 per cent of the cabling has been laid, connecting the tunnel, bridge, and control buildings. Remaining installations are due to be completed over the coming weeks.

So far, the project has delivered over 20 miles of cabling installed through the tunnel; extensive civil works, including piling up to five metres deep and concrete pouring; removal of old gantries and installation of four new 5x9-metre gantries; new internal tunnel gantries and easy-access duct covers and the replacement of sensors to improve air quality monitoring.

Julian Mitchell, National Highways tunnel manager, said: “This generational, £25-million upgrade is a complex operation, overhauling outdated systems, and will deliver major safety, traffic flow and air quality benefits for many years to come.

“It’s difficult to work safely within and around the structure without closing it overnight and we thank people for their patience while we continue towards completion of the scheme.

“We’re doing everything we can to minimise disruption for local communities, and users of the tunnel and Tamar Bridge, the work is planned carefully with our partners and we are keeping all stakeholders informed in the meantime.”

The new tunnel and traffic control system, which is currently undergoing testing off site, will replace the outdated tidal lane system, which was decommissioned earlier this year.

Fixed lanes were introduced in late May, providing two westbound lanes through the tunnel and across the Tamar Bridge, and one eastbound lane for traffic heading into Plymouth. Local traffic and Tamar Tag holders continue to use the cantilever link.

Over the coming months, technology installations are continuing in and around the tunnel, under overnight closures (8pm to 6am) on weeknights only, with a pause between December 19 and January 2, for the Christmas holiday period. As work continues, speed restrictions will remain in place.

So far, 70 per cent of the cabling has been installed between the tunnel, bridge and control buildings, with the remainder being fitted and connected in the coming weeks before the system is fully connected.

When complete, the new control system will include: energy-efficient LED lighting; a modern ventilation and air quality system; fibre cabling for advanced power distribution and improved information signage and driver messaging.

For live updates, motorists can visit www.trafficengland.com, follow @HighwaysSWEST on X (Twitter), or call the National Highways Information Line on 0300 123 5000.