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.
Trafalgar Square proposed budget cuts. During the night the situation turned violent as the escalation by riot police and protesters damaged portions of the square. In November 2015 a vigil against the terrorist attacks in Paris was held. Crowds sang the French national anthem, "La Marseillaise", and held banners in support of the city and country. Every year on the anniversary of the Battle of Trafalgar (), the Sea Cadet Corps holds a parade in honour of Admiral Lord Nelson and the British victory over the combined fleets of Spain and France at Trafalgar. The Royal British Legion holds a Silence in