Ceremony of the Keys (London) after the Tower. The event is usually sold out at least 12 months in advance. Ceremony of the Keys (London) The Ceremony of the Keys is an ancient ritual, held every evening at the Tower of London, when the main gates are locked for the night. It is said to be the oldest military ceremony in the world, and is the best-known ceremonial tradition of the Tower. At exactly 9.53 pm, the Chief Yeoman Warder, dressed in Tudor watchcoat and bonnet, and carrying a candle lantern, leaves the Byward Tower and falls in with the Escort to the Keys, a
The Keys of Marinus weapon, and Ian is freed. The travellers return to Arbitan's island, where Altos and Sabetha have been held prisoner by Yartek—Arbitan's killer—and the four keys have been seized. The Doctor frees Altos and Sabetha and unmasks the Voord. Ian gives Yartek a false key found in the screaming jungle; when Yartek places the key in the Conscience, the machine explodes and he is killed along with the occupying Voord. The Doctor, Susan, Ian and Barbara flee the tower with Altos and Sabetha before the growing blaze overtakes the ancient structure. "The Keys of Marinus" was written to replace a different