Longdon-upon-Tern

	Telford's practice piece has all the features of the final work

When Thomas Telford was confronted with the problem of how to cross the River Dee near Llangollen he thought of that new material - cast iron. But dare he risk it on such an important part of his canal scheme?

Luckily there was another river that needed to be crossed by his canal, neither as high nor as wide as the Dee, which made it the ideal place in which to experiment. The site had the additional benefit of being in the middle of nowhere, so even if the aqueduct failed, there was no one around to see and mock.

Unfortunately, the branch of the canal on which the experiment stood has now closed and been ploughed out, so the aqueduct stands forsaken as a rather pointless trough over the River Tern.