Brunel's swing bridge alongside north entrance lock

The swing bridge, designed by Isambard Kingdom Brunel, was built between 1849 and 1850 and later moved to its current location with alterations in 1873. It has undergone repairs in the 21st century.

Constructed from wrought and cast iron, with additional repairs in cast iron and steel, the bridge is currently in its open position, parallel to the south side of Howard’s Lock, and measures 33.7 meters in length. It features a balloon flange girder design, consisting of tubular section long members, wrought-iron tie bars, side panels, and flanged plate girders that provide support for the deck. The original timber deck covering has been removed. The transverse beams are set diagonally, and the turntable beams are connected to a pivot pin located in a wheel pit with an iron ring.

Inside the pit, four iron wheels, one of which is a 21st-century replacement, rest in plummer blocks. These wheels facilitate the turning of the bridge via a turntable ring that has a 21st-century steel track. The outer wheels are supported by a sunken iron rail, which ends at a timber bollard. Additionally, inspection panels in the ground beneath the bridge cover the machinery used to operate the swing bridge and are lined with riven stone setts.