Thomas Telford carried out a significant amount of work in Wales, particularly in the north, and much of today's transport infrastructure incorporates, or was developed from, his works.

Telford's influence on North Wales began with his earliest work as Surveyor of Public Works in Shropshire. His first bridge over the River Severn at Montford still stands and it carried the London to Holyhead road (A5) until a few years ago.

His many other River Severn bridges must also have greatly improved communications across the border at the time, and it is believed he carried out maintenance and improvements to the vitally important English and Welsh bridges at Shrewsbury itself.

His work in engineering the Ellesmere canal with its world famous aqueducts took Telford deep into the heart of North Wales.

Having investigated various routes for a new road from Shrewsbury to Holyhead in order to improve travel and communications with Ireland following the Act of Union, Telford was appointed to build the road in 1815.

This was a vast undertaking involving some 85 miles of mostly new road through some of the most difficult terrain in Wales. Most of this route is still in use carrying modern trunk road traffic, although its appearance is much altered in many places.

The project involved the construction of a large number of significant structures of various types, including the high retaining walls at Nant Ffrancon in Snowdonia, the 1,300 yard (1,180m) long Stanley embankment near Holyhead (1823-1824), and the iconic and world famous Menai Suspension Bridge (1818-1826).

At Nant Ffrancon he achieved a maximum gradient of 1 in 22 which contributed greatly to the overall average speed of coach travel on the route and the reduction in total journey time.

The retaining walls have survived a number of landslides and were strengthened (and preserved) by 'soil nailing' in the 1990s.

The construction of the Stanley embankment, apart from by-passing the only previous crossing of the narrow tidal strait between Anglesey and Holy Island, created the 'inland sea' which became a significant ecological feature and was designated as an SSSI in 1961.

Menai Bridge had to be constructed without obstructing navigation in the Menai Strait and at a height of 100ft above high water. With a span of 580ft (176m), the bridge was 30% longer than any previous suspension bridge and a number of significant initiatives were involved in its construction.

The raising of the great wrought iron chains attracted much attention and admiration and contrasted with the somewhat low-key first crossing of the bridge by the post coach in the wet early hours of 31 January!

Other notable elements of the road project include Waterloo Bridge at Betws y Coed (1816), the retaining walls and bridge at Pont Padog, Pont Ben y Benglog (Llyn Ogwen), two main designs of tollhouse (those on Anglesey being particularly noteworthy), and building new coach-stop hotels such as Mona Inn on Anglesey.

Telford was also responsible for innovations in procurement procedures and supervision arrangements, establishing a tendering and contract administration model which was widely adopted throughout the industry, and developed as required to meet changing circumstances.

It is recorded that contractors were prepared to rely on Telford's personal qualities of experience and fairness in resolving any disputes which were referred up to him to determine.

His appointment was extended to include the road from Chester to Bangor, requiring new roads around the previously extremely hazardous headlands at Penmaenmawr and Penmaenbach, which were not further improved until the 1930s.

It also involved building another suspension bridge with a long 'cob' to cross the River Conwy (1826), and improvements to the route between St Asaph and Holywell (including Rhuallt Hill).

Telford was also responsible for the survey of around 450 miles of road in South Wales for the Government between 1823 and 1825, although it seems that his proposals for improvements were not developed.

By Bob Daimond, first published by the Newcomen Society