Jetty Number 4 and Approach, Formerly at Samuel Williams and Company, Dagenham Dock

This is a coaling jetty dating from 1899 to 1903, originally built for Samuel Williams & Sons Ltd. Designed by L. G. Mouchel & Partners, it utilized Hennebique's patent system for reinforced-concrete construction. An extension was added in 1906-7, designed by Arthur E. Williams, who incorporated his own patented system for the horizontal casting of reinforced-concrete piles, developed to address issues encountered during the initial construction.

The jetty is approximately 500 feet (150 meters) long and runs parallel to the north bank of the Thames in front of Dagenham Dock. The approach from the shore, about half the length of the jetty, is angled at roughly 45 degrees and runs from an easterly point on the shore to meet the jetty near its east end, creating a layout resembling an asymmetrical "T" shape like a handgun. The jetty consists of 13 bays – 10 bays to the west of the approach, one bay to the east, and two bays at the junction where the approach meets the jetty, with each bay being roughly 40 feet (12 meters) square. The bays west of the approach were widened to the north during the mid-20th century, tapering towards the west end.

The original reinforced-concrete structure is largely intact, though partially obscured by mid-20th-century additions. The construction is described as a trabeated or post-and-lintel design, featuring robust cylindrical piers on pile foundations with cushion capitals supporting platforms or floors framed by grids of girders. Horizontal cross braces, some of which are broken, link opposed pairs of piers. Early braces and girders exhibit chamfered arrises.

The approach, consisting of 10 bays, is built in a similar style, with slightly less substantial piers, cushion capitals, and platform ramps that gradually rise from the shore to the jetty. The piers and one bay of platform at the jetty end of the approach are more robust, featuring cross braces. Girder ends on the approach project slightly over the pier capitals. The railings have been renewed, but an original parapet panel with a coped cornice head remains on the east side of the approach, on the shore side. Both the jetty and the approach contain disused tracks for cranes and railway wagons.

The jetty is historically significant as one of Britain's earliest surviving reinforced-concrete structures, further distinguished by the innovative use of Williams’s patented piles, a notable advancement in civil engineering. While the reinforcing steelwork and later additions from the mid-20th century and beyond are not of special interest, the remaining original structure retains considerable architectural and historical value.