Nick Young wrote in The Londonist of 24 August 2015:
“…On the western side of Trafalgar Square, the maple leaf flag flies proudly from Canada House, which boasts one of the most famous diplomatic addresses in the world. When the Canadian government acquired what had previously been the Union Club in 1923, the then Canadian Prime Minister Mackenzie King declared it to be “the finest site in London and, being in London, the finest in the world”. Following a recent refurbishment, Canada House was reopened by the Queen – she’s Queen of Canada, too – earlier this year.
What is perhaps less well known is that back when the Canadians first moved in, the area was known as ‘Little Canada’. Next door to Canada House is 2-4 Cockspur Street, which was built in the 1920s by the Sun Life Assurance Company of Canada, and during the Second World War it served as the Canadian Military Headquarters in Britain. It is now part of the Canadian High Commission.
Just across the street from Canada House, at 62-65 Trafalgar Square, is the Canadian Pacific Building. It now sports a Pret on the ground floor but the name of one of Canada’s two railway companies is clearly visible at the top, next to a clock which is one of just two that looks out onto Trafalgar Square (the other one is on St Martin-in-the-Fields).
The other railway company was originally the Grand Trunk Railway, and later became the Canadian National Railway. It had its headquarters at 17-19 Cockspur Street…
The Grand Trunk Railway Building on Warwick House Street in London continues to stand. Built by Aston Webb, the 7 storey building was built in 1907 with the banner (see image) The Grand Trunk Railway of Canada on 4 Warwick House Street and Canadian National Railway on Cockspur Street. CN no longer owns the building.
The Grand Trunk Railway (reporting mark GT) was a railway system that operated in the Canadian provinces of Quebec and Ontario and in the American states of Connecticut, Maine, Michigan, Massachusetts, New Hampshire, and Vermont. The railway was operated from headquarters in Montreal, Quebec, with corporate headquarters in London, England (4 Warwick House Street).)
It hasn’t all been one-way traffic though. When the fountains in Trafalgar Square were replaced in the mid-twentieth century, the originals went to Canada; one is in Ottawa, the capital, while the other is in Regina, Saskatchewan…
Ashley Prime added a Comment: “…the damaged granite blocks on the plinth of Nelson’s Column were caused by Canadian soldiers burning the wooden holdings they pulled down from around Trafalgar Square on Armistice Day 1918.” “