In 2011, in support of Argentina's claim to the islands, the members of Mercosur banned Falklands flagged vessels from entering their ports. Vessels flying the Falklands Civil Ensign are required to re-flag with the Red Ensign to enter Mercosur ports. The flag was flown from several HM Government buildings in London, including 10 Downing Street and the Foreign and Commonwealth Office in Whitehall, on 14 June 2012 to mark the 30th anniversary of the islands' liberation. For the majority of the Falkland Islands existence as a British territory, the appropriate civil ensign was the same as that of the United Kingdom, an undefaced red ensign. The first warrant issued for the use of a defaced red ensign was issued in 1998, to be effective on 25 January 1999. This warrant prescribed the coat of arms of the Falkland Islands within a white disc. However, a revision of territorial flags issued later that year removed the white disc and enlarged the territorial emblems across the board.