A Grade II* listed building,[1] it is built on a skew of 40° across Store Street, and is believed to be the first major aqueduct of its kind in Great Britain and the oldest still in use today.

It is built of stone with large voussoirs and retaining walls of coursed masonry and is 7.4 metres (24 ft) wide with triangular buttresses.

It had not always been acceptable but attempts to build masonry arch bridges at an angle, or "skew", of greater than about 15 degrees had proved unsatisfactory.

Although the aqueduct still exists, and is structurally sound, years of neglect led to water leakage through the joints, and the spiral construction can no longer be seen, the surface of the intrados having been rendered.

Later railway engineers improved on the system, producing what became known as helicoidal construction that became the norm in English skew bridge building.