Ceremony of the Keys (London) through the Bloody Tower archway. The Chief Warder and the escort were blown off their feet, but they recovered and carried on. The Tower holds a letter from the Officer of the Guard apologising to King George VI that the ceremony was late, along with a reply from the King which says that the officer is not to be punished as the delay was due to enemy action. Between 40 and 50 visitors are allowed access to the ceremony each night, under escort. Tickets are free but must be obtained in advance from Historic Royal Palaces, the organisation that looks
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