Second World War. During much of the First World War, the Honourable Artillery Company (HAC) provided the Tower garrison but in 1919 after handing back the Tower Guard to the Foot Guards, the HAC's 3rd Battalion presented a lantern to the Yeomen Warders on the 12 May 1919 as a mark of friendship during their time on duty. The lamp was used for the ceremony of the keys that night and every night ever since. Access Between 40 and 50 visitors are allowed access to the ceremony each night, under escort. Tickets are £5 and must be obtained in advance from Historic Royal Palaces, the organisation that looks after the Tower. The event is usually sold out at least 12 months in advance. Following the suspension of public visits during the COVID-19 pandemic, the ceremony was opened to the public again from 1 June 2021. References External links A 1936 BBC recording of the Tower of London ceremony: Order of the Ceremony of The Keys (London), a personal website describing the ceremony (with photographs) State ritual and ceremonies 14th-century establishments in Europe Tourist attractions in the City of London Events in London Tower of London Ceremonies in the United Kingdom