3. Masterpiece

Thomas Telford's extraordinary career reached its zenith with the construction of the Pontcysyllte Aqueduct, begun in 1795 and opened in 1805.

Still in use today, carrying the Llangollen Canal, it towers 100 feet high and a 1,000 feet long over the valley of the River Dee. Built with simple technology, no safety ropes and no experience of building anything so high, unusual care was paid to protecting the workforce: only one man died during construction (and that death was thought to be due to carelessness).

It is seen as Telford's masterpiece and he chose it above all of his creations as the background to his official portrait in the Institution of Civil Engineers.

Julian Glover has written the first full modern biography of Thomas Telford: a shepherd's son, who revolutionised British engineering and set the stage for the Industrial Revolution.

Read by Robin Laing.

Abridged by David Jackson Young

Producer: Kirsteen Cameron.

First broadcast on BBC Radio 4 in January 2017.