Historian Peter Brown champions the unsung heroes of Pontcysyllte Aqueduct.
Who built Pontcysyllte Aqueduct, that magnificent icon of the Canal Age? Surely everybody knows it was Thomas Telford. It wasn’t as simple as that. The highest, longest and most elegant aqueduct in Britain was built to satisfy business needs, not to demonstrate engineering skills.
The idea for a canal from the Severn to the Mersey wasn’t Telford’s. The owners of ironworks in the Ruabon and Wrexham area wanted to bring quality limestone to their furnaces and to get their products to market. The gentry of north Shropshire wanted limestone to improve their lands. They got together and employed John Duncombe, a local surveyor, to see whether the project was feasible. He said it was, so they then engaged William Jessop, the country’s leading canal engineer, to check the survey, design the canal and help persuade Parliament to allow them to go ahead.
Having raised the necessary money and got their Act, the canal company confirmed Jessop as their engineering adviser. They also appointed their key full-time staff: Duncombe as resident engineer and the 36-year-old Thomas Telford as general agent – or, in modern terms, general manager.
Telford had trained as a stonemason, had supervised building works, and five years earlier had moved to Shrewsbury to be an architect. But the town already had two good architects and he found little work. Through political patronage the local justices made him county surveyor, a part-time post responsible for bridges and public buildings. He impressed them with his design ability and organisational skills, and this led to his canal appointment.
Jessop’s route involved a high-level aqueduct across the River Dee at Pontcysyllte. The design adopted was innovative: tall masonry piers with spans and a trough of cast iron. We don’t know for certain whose idea this was. It could have been Telford’s, as he was then in close contact with William Reynolds, the ironmaster who that year probably did most of the design work for the iron aqueduct at Longdon-on-Tern on the Shrewsbury Canal. Or it could have been Jessop’s, as he was quarter-owner of the Butterley ironworks in Derbyshire so was well aware of the possibilities. What is certain is that it was Jessop who was responsible for advocating such a structure to the canal company. He also recommended the number and size of the piers, and that their upper sections should be hollow.
The detailed design, including the spans and trough, was probably done by Telford. As iron was such a new material for large-scale construction, he no doubt worked closely with William Hazledine, the ironwork contractor, and with William Stuttle, Hazledine’s foreman, who would actually have to produce the castings.
Because Jessop was then also working on several other projects, he left the detailed management to Telford. No doubt he was happy to do this as he knew there was such a competent person on the spot.
Overall control lay with the canal company’s committee – men like John Hill, Rowland Hunt, John Kynaston and John Lloyd, all now forgotten except by local historians. Without them the scheme would never have happened. The engineering aspects were led by William Jessop and Thomas Telford, with inputs from William Hazledine and William Stuttle. And we mustn’t forget John Simpson, the contractor for the stonework, and Matthew Davidson, who day-to-day supervised the construction. Together with the stonemasons and the foundrymen, they built Pontcysyllte Aqueduct. It was orchestrated talent and effort that created this landmark, not the stellar efforts of one soloist.
Written by Peter Brown
Last date edited: 12 May 2020