He was responsible for some of the most innovative work on tunnels and bridges in the United Kingdom in the 40-year period centred on World War I.
Shortly after Greathead's death in October 1896, Benjamin Baker formed a partnership with Mott for the design of the Central London Railway.
Their association continued with the extensions and rebuilding on the C&SLR (including the underpinning of St Mary Woolnoth church at Bank) and the widening of Blackfriars Bridge.
During the first world war, Basil Mott visited France and India, advising the government on solving engineering problems.
His partnership (by then named Mott, Hay and Anderson) designed and supervised the construction of the Mersey Tunnel in its entirety.
[3] In 1926 he was hired by Southampton council to investigate the various options for building a fixed crossing across the lower River Itchen.