When Thomas Telford became chief engineer of the Shrewsbury Canal project, one of his first tasks was to bridge the River Tern at Longdon. A masonry aqueduct begun by his predecessor had been swept away in the floods of February 1795 and Telford was persuaded by the canal company’s promoters to consider a new material for its replacement – iron.
Longdon Aqueduct is the oldest surviving cast iron structure of its kind in the world but was not the first to be built. A few weeks before its completion, in February 1796, the much smaller Holmes Aqueduct, designed by the civil engineer Benjamin Outram, opened on the Derby Canal. Sadly, this historic structure was demolished in 1971.