Thomas Telford Llangollen canal tunnels given check-ups

They were dug out of the hills 200 years ago to carry Thomas Telford's Llangollen Canal in north Wales.

Two centuries on, those tunnels are being given some vital check-ups as part of a £40m investment in the maintenance of Britain's canals.

Tunnel inspector Chris Reynard described the checks being carried out in the Chirk Tunnel.