Built of brick by the Midland Railway and opening in 1868, it is notable for its extreme skew angle of approximately 65°.

[1] Located approximately 0.8 miles (1.3 km) south of Harpenden station, the bridge was built to carry a double-track standard gauge railway line across Southdown Road, which borders Harpenden Common in Hertfordshire, as part of the Midland Railway's southern extension towards its London terminus at St Pancras, and opened to traffic in 1868.

The easiest way to visualise Boucher's concept for the ribbed skew arch is to consider a regular arch bridge that carries the railway at right angles across the road and then to slice it vertically at regular intervals along the axis of its barrel, the planes all being parallel with the faces of the bridge, rather like the way a loaf of bread is sliced.

The individual slices are then slid laterally with respect to one another in order to achieve the required oblique alignment.

Thus, the need to lay helical courses of brick at such an extreme angle to the horizontal is avoided as the multitude of conjoined regular arches approximate the desired structure.