Nelson's Column was planned independently of Barry's work. In 1838 a Nelson Memorial Committee had approached the government proposing that a monument to the victor of Trafalgar, funded by public subscription, should be erected in the square. A competition was held and won by the architect William Railton, who designed a Corinthinan column topped by a statue of Nelson. The proposed height was 218 feet 3 inches (66.52 m), at the base it is guarded by four sculpted lions. The design was approved, but received widespread objections from the public. Construction went ahead beginning in 1840 but the height was reduced to 145 feet 3 inches (44.27 m).[24] The column was completed and the statue raised in November 1843.[25]
The last of the bronze reliefs on the column's pedestals was not completed until May 1854, and the four lions, although part of the original design, were only added in 1867.[26] Landseer, the sculptor, had asked for a lion that had died at the London Zoo to be brought to his studio. He took so long to complete sketches that its corpse began to decompose and some parts had to be improvised. The statues have paws that resemble cats more than lions.[27]
Barry was unhappy about Nelson's Column being placed in the square. In July 1840, when its foundations had been laid, he told a parliamentary select committee that "it would in my opinion be desirable that the area should be wholly free from all insulated objects of art".[20] The hoardings were removed and the square opened to the public on 1 May 1844, although the asphalt paving was still soft and the fountains were not working. A hoarding remained around the base of Nelson's Column for some years and some of its upper scaffolding remained in place.[28]
The square has become a social and political focus for visitors and Londoners, developing over its history from "an esplanade peopled with figures of national heroes, into the country's foremost place politique", as historian Rodney Mace has written. Its symbolic importance was demonstrated in 1940 when the Nazi SS developed secret plans to transfer Nelson's Column to Berlin[b] after an expected German invasion, as related by Norman Longmate in If Britain Had Fallen (1972