George, Duke of Cambridge

A statue dedicated to a man depicted on horseback sat atop a plinth which bore his name. According to the plaque, he was born in 1819, served or held some title in the British Army between 1856 and 1895, and died in 1904.

In 2167, Dortmun, Barbara Wright and Jenny Chaplin hid from the Daleks behind the plinth, which was right near Trafalgar Square in London. (TV: "Day of Reckoning")

Behind the scenes
Though the full plaque isn't visible, this is Prince George, Duke of Cambridge, who was in fact Commander-in-Chief of the British Army between 1856 and 1895, a detail which is just out of frame in The Dalek Invasion of Earth. Prince George was George III's grandson, and Queen Victoria's cousin.

The statue in Whitehall is located directly outside the entrance to the War Office.