 Along with proving costs for a tunnel and a high level crossing he recommended a low level opening span bridge.Basil Mott's other post-WW1 works include the extension to Morden of the Northern line, the enlargement of the original C&SLR tunnels from 10' 6" to 11' 8" (using a tunnelling shield which could be worked at night but through which trains could drive during the day), the Jubilee Bridge and work on the Tees Newport Bridge.In 1930, aged 71, he gave evidence to a British government inquiry on the engineering aspects of a proposed Channel Tunnel (which was not built, though Mott, Hay and Anderson designed the bulk of the successful scheme for Channel Tunnel half a century later).