[2] The valley of the River Welland was a major geographical obstacle along the selected route for the line requiring the construction of a lengthy viaduct.

[3] A contract for the construction of the viaduct was tendered, to which London-based civil engineering firm Lucas and Aird was awarded prime contractor status.

[2] The viaduct, which crosses both the Welland Valley and its flood plain, was designed by William Henry Barlow and members of his company, including his son Crawford, who was the resident engineer, and his former pupil Charles Bernard Baker.

[2] In 1875, Cyprus Camp was built at the north end of the viaduct adjacent to the village of Seaton to house construction workers and their families.

An account of the workers, Life and Work Among the Navvies, was written by Reverend D. W. Barrett, the vicar of Nassington, curate-in-charge of the Bishop of Peterborough's railway mission.

[7][9] At the time of its construction, only the elevated multi-track approach to London Bridge railway station exceeded the viaduct's length of 1,280 yards (1,171 metres).

[3] On 1 October 1885, the "Slip Coach", entered service to connect with fast trains to London, Northampton, Cambridge and the Eastern Counties at Kettering.

[11] During the First World War, the viaduct was attacked by a German Zeppelin, possibly because of its strategic importance in transporting troops to the ports on the English Channel.

[12][1] In 1939, bombing threats issued by the Irish Republican Army (IRA) resulted in the area around the viaduct being placed under guard by police.

[13] In 1967, as a consequence of the Beeching cuts, scheduled passenger services over the viaduct were discontinued, but the line remained open for freight traffic.

Traditional methods and materials were employed alongside modern access techniques to ensure the viaduct's long-term structural integrity.

Vertical cracks were fitted with 6mm stitch bars where applicable, and galvanised steel angle brackets were fixed onto either side of joints where the outwards lean exceeded 40 mm.