Medieval tunnel discovered along Welsh-English border

Workers excavating a trench near the Welsh-English border have discovered a centuries-old tunnel, which may date back to the Middle Ages.

A team from Western Power Distribution (WPD) were in Tintern, situated in the heart of the Wye Valley, where they began excavation work following a customer request for the relocation of a pole on their property


WPD Technician Allyn Gore, who headed up the team, explains: “Before work began, all the usual checks and permissions were in place, thanks to Wayleave Officer Luke Summers. Nothing had shown up on any of our drawings or records to indicate there was anything unusual about the site. We needed to move the existing wooden pole, and underground a span of cable, because if we used an angled stay on the new pole, it would impede walking on a footpath there.

“Shortly after the excavation work began, the digging team made the extraordinary discovery of what they initially thought to be a cave. Work stopped immediately and Luke and I were called to site to decide what course of action we should take next. I have been involved in other excavations where we have discovered old wells and cellars not shown on any plans, but nothing as exciting and impressive as this,” said Allyn.


“Further investigation revealed it was a manmade tunnel around 4ft in height. The tunnel system was tucked away underneath a footpath, running parallel to the Angiddy Brook, and seemed to follow the brook’s route along the valley; it may have been unknowingly walked on for centuries.

Medieval tunnel discovery by East Mon Team recently in the Wye Valley. Photo courtesy Western Power Distribution

“Team Manager, Bradley Griffiths, contacted Cadw (the Welsh Government’s historic and cultural heritage service), who sent a representative along to the site. He was very impressed with the sheer scale of the tunnel and quite fascinated to see it. In his opinion, it could possibly be linked to the iron work ruins previously discovered in the area,” said Allyn.

The ruins of Tintern Abbey date back to the 1100s and are just a short distance away the valley, which has an abundance of ruins from old furnaces, iron works and forges. This tunnel is not shown on any ordinance survey maps dating back as far as the 1700s and none of the local residents or authorities have any knowledge or record of this particular tunnel system.

After consultations with Cadw, it was decided to stop all work and seek an alternative route to prevent the risk of damaging or reducing the integrity of the tunnel, while further investigations take place by archaeologists.


Allyn explained: “For now, we have backfilled the trench and re-instated everything and we are planning an alternative route for the customer. It could take years before the investigations are concluded.”