The Dene Triangle Sowerby Bridge
Like me, David Fletcher was probably taught at school that the great bridge over the Severn at Ironbridge was the world's first iron bridge ("The birthplace of the world's first industrial revolution", Courier July 31).
Iron it is and oldest surviving it may be, but first it isn't. That oft-repeated error does Calderdale and Yorkshire a disservice.
When Abraham Darby's remarkable structure was opened in Shropshire, other iron bridges had been around in Yorkshire for some time. The following appeared in the Leeds Intelligencer on February 2, 1770, at least nine years earlier:
"A few days ago was finished by Mr.Tobin of this town, a most curious bridge of one arch, six feet wide, and seventy-two feet in span; made entirely of iron; and is thrown over a canal in Sir George Armitage's park at Kirklees in this county.
"It has also iron ballustrades (sic), which are ornamented with roses of the same metal; may be taken to pieces at pleasure, and is thought the greatest curiosity of the kind that was ever exhibited in this part of the country."
It is Mr Tobin's and Sir George Armitage's misfortune that their bridge in Calderdale did not survive into an age that respects artefacts from the industrial revolution.
Slightly earlier, a cast-iron bridge of 1769 carried the Great North Road over the River Ure Navigation at Boroughbridge but collapsed under a heavy load in 1946.
Walton Hall, dating from 1767 near Wakefield, is still reached by an iron bridge over the moat.
By its construction it is very early but little is known of its origins. Earlier still there may have been iron bridges in France and China.