Designed by John Rennie the elder and opened in 1819, the cast iron bridge at Southwark was the state-of-the-art in bridge building at the time, with three flat arches supporting a 42-foot-wide roadway. The centre arch, at 240 feet, was the longest of its kind ever constructed. The width was a requirement, because of fears of obstruction to the navigation on the Thames. The bridge was rebuilt in 1921.
