A bronze figure of Indian civil rights leader Mahatma Gandhi now stands opposite the Houses of Parliament.
The statue, marking the 100th anniversary of Gandhi's return to India to start the struggle for self-rule, was unveiled by Indian finance minister Shri Arun Jaitley.
The unveiling ceremony included a tribute from Gandhi's grandson, the former governor of West Bengal, Sri Gopalkrishna Gandhi.
"It also marks an important, historic moment celebrating the strong bond between our two nations," Jaitley said in a statement before the unveiling. "India and the UK share the same values and we are a partnership of equals. This lasting friendship is just one of many legacies left by Gandhi."
The Gandhi Statue Memorial Trust raised more than £1m for the work and described it as a "magnificent tribute".
The bronze statue of Gandhi was made by British sculptor Philip Jackson and shows the Indian leader dressed in a shawl and traditional dhoti skirt. It is based on a number of photographs, including a picture of Gandhi standing outside the London offices of the British prime minister in 1931.
British Prime Minister David Cameron said: "This statue is a magnificent tribute to one of the most towering figures in the history of world politics and by putting Mahatma Gandhi in this famous square we are giving him an eternal home in our country.
"Many of his teachings remain as potent today as when he first made them.
"'The best way to find yourself is to lose yourself in the service of others' and 'be the change that you want to see in the world' remain timeless, profound and inspiring words of wisdom."
Parliament Square also includes statues of former US President Abraham Lincoln and South African President Nelson Mandela.
Ironically, Gandhi's statue is near Winston Churchill's. The British prime minister during the Second was opposed to Indian independence and once described Gandhi as "a seditious Middle Temple lawyer, now posing as a fakir of a type well-known in the East, striding half-naked up the steps of the Vice-regal palace".