Throughout 2025, Glandŵr Cymru, the Canal & River Trust in Wales, and its partner organisations and local community are celebrating the 225th anniversary of the Brecon Canal.

The Monmouthshire & Brecon Canal began life as two separate canals – the Monmouthshire Canal and the Brecknock & Abergavenny Canal. Although the two were joined in 1812 at Pontymoile, this year’s anniversary celebrates the completion of the more northern Brecon Canal 12 years earlier.

David Viner, heritage consultant at Canal & River Trust, is telling the story of the canal throughout the year, with his next stop at the Ashford Tunnel.

By the end of 1797, with the canal to Brecon nearly half completed after only a year, the shareholders of the Brecknock & Abergavenny Canal Company must have been very satisfied with progress.

The next stage, however, did not go so well. At Ashford, three miles on from Llangynidr, the 1794 survey had recommended a tunnel: to avoid the steep and slippery bank by the side of the river, along which the canal cannot be carried, but at a great expense, as well as the uncertainty of supporting it.

It was the only one required between Gilwern and Brecon. There was no space for a towpath, so horses were led over the top and boats were propelled by men lying on a board “legging” against the tunnel wall.

Early tunnels were beset with building problems and this one was no exception. When two thirds completed, part of the roof collapsed due to unstable ground and a long section had to be rebuilt.

The contractor, Thomas James, complained bitterly that he had done everything according to the engineer’s requirements and the fault really lay with Dadford’s design and cost savings. The 375-yard tunnel wasn’t finished until the autumn of 1799, costing nearly three quarters more than the original estimate.