Trafalgar Square Authority in conjunction with the charity Unicef, who began ticketing the event to control crowd numbers. A Christmas ceremony has been held in the square every year since 1947. A Norway spruce (or sometimes a fir) is presented by Norway's capital city, Oslo as London's Christmas tree, a token of gratitude for Britain's support during World War II. (Besides war-time support, Norway's Prince Olav and the country's government lived in exile in London throughout the war.) The Christmas tree is decorated with lights that are switched on at a seasonal ceremony. It is usually held twelve days before Christmas Day.
Fourth plinth, Trafalgar Square recommended that the plinth should continue to be used for an ongoing series of temporary works of art commissioned from leading national and international artists". After several years in which the plinth stood empty, the new Greater London Authority assumed responsibility for Trafalgar Square and the fourth plinth. The Fourth Plinth Commission is led by the Mayor of London's Culture Team, under the guidance of the Fourth Plinth Commissioning Group. The group is made up of specialist advisers appointed to guide and monitor the commissions for the plinth. Under the stewardship of the Fourth Plinth Commissioning Group, the following artworks