Primrose Hill Tunnels (Eastern Portals)

Pair of railway tunnel portals at the eastern end of the Primrose Hill Tunnels, designed by William Budden for the London and Birmingham Railway. The northern portal dates from 1837 and the southern from 1879.

The northern portal, built in 1837, is constructed of stock brick and stone with stone dressings. It features a round-arched tunnel mouth with coved reveals of rusticated voussoirs, crowned by a heavy modillion cornice with carved lion masks. The opening is flanked by massive stone piers on vermiculated stone pedestals with long and short quoins and console bracketed hipped capitals designed to appear as ridged lead roofs. Flanking the piers are quadrant brick wing walls, also with vermiculated stone podiums, broken by channelled stone pillars crowned by segmental pediments.

The southern portal of 1879 faithfully replicates the design of the original portal down to decorative detail such as the lion masks, differing only in being taller to accommodate the rising land towards Primrose Hill.

The northernmost tunnel was completed in 1837 and was the first railway tunnel in London and one of the earliest in the country. It was built for the London and Birmingham Railway Company and engineered by George Stephenson and Son, with the portal designed by William Budden, Stephenson's assistant. A second tunnel to the south, with a portal in the same design as Budden's original, was completed in 1879 following the addition of a further two tracks to the line in 1846.

The land was part of the Chalcots Estate, owned by Eton College and largely rural in 1837. The College, which had begun developing the area from 1830 with Adelaide Road, initially opposed the railway proposals fearing damage to land values and house leases. This opposition necessitated the tunnel's construction. The College insisted on a bored tunnel rather than cut and cover, despite the gradient allowing track to be laid without one. The Act of Parliament of 1833 stipulated that the tunnel be constructed with sufficient strength for buildings to be erected at ground level. The College also demanded that the tunnel mouth be "made good and finished with a substantial ornamental facing of brickwork or masonry to the satisfaction of the Provost and College". The resulting portal cost £7,000 and was more grand than the Western Portal.

Before houses encroached on the approach, the sloping sides of the cutting provided viewing points for members of the public watching the trains and portal. The scene was depicted in a watercolour by J H Nixon after a painting by J Cleghorn of 1837 and a lithograph by C Rosenberg.

The London and Birmingham Railway opened in 1838 and was one of the first intercity railway lines in the world and, after the London to Greenwich Railway of 1836, the first major railway line to be built into London. The line was engineered by Robert Stephenson and started at Euston Station. It was one of the most significant engineering projects of the 19th century and a landmark in pioneering railway technology worldwide. The second tunnel to the south became operational in June 1879.