MACCLESFIELD BRIDGE 1815 Regent’s Canal, London HEW 2246 TQ275 833 N51o 32' 4.8" W0o 9' 47.0"
This is an early use of cast iron columns to support the springing of the arches of a conventional brick bridge. It was designed by James Morgan who was assistant to John Nash and engineer to the Regent's Canal Company of which Lord Macclesfield was Chairman. This bold bridge which carries Avenue Road over the canal into Regent's Park has three arches supported by iron Doric columns cast at the Coalbrookdale Company iron works. When a barge carrying gun powder blew up under the bridge in 1874, the bridge and parts of the immediate neighborhood were demolished. The iron columns survived and were used in the replacement 1876 bridge with only a few dents and scars testifying to their adventure. Similar cast iron Doric columns support the Nene railroad bridge arches at Petersborough.
To find it, take the Underground to St. John's Wood Station and on coming out, take a left onto Acacia Avenue (away from Finchely/Wellington Road). It is a fairly long walk through a beautiful neighborhood of Georgian houses to Avenue Road where you take a right. You will find the canal and the bridge in a few blocks.