The Engineer has covered multiple attempts to connect the UK to mainland Europe, with only one project succeeding thus far. James Chalmers of Montreal proposed a unique method of connecting sections of tube and submerging them under the English Channel, rather than digging a tunnel. His design included a circular section tubular roadway with an inner rectangular way to divide water pressure. Chalmers’ career included inventing the Chalmers Target and writing a book on naval construction. Unfortunately, he passed away at 49, leaving his widow and family in financial hardship. The Engineer highlighted his contributions to the public service and hoped the government would recognize them.
https://www.theengineer.co.uk/content/archive/november-1861-chalmers-under-channel-railway/