The Yeomen Warders of Her Majesty’s Royal Palace and Fortress the Tower of London, and Members of the Sovereign's Body Guard of the Yeoman Guard Extraordinary, popularly known as the Beefeaters, are ceremonial guardians of the Tower of London. In principle they are responsible for looking after any prisoners in the Tower and safeguarding the British crown jewels, but in practice they act as tour guides and are a tourist attraction in their own right, a point the Yeomen Warders acknowledge.
In 2011, there were 37 Yeomen Warders and one Chief Warder. All warders are retired from the Armed Forces of Commonwealth realms and must be former senior non-commissioned officers or petty officers with at least 22 years of service. They must also hold the Long Service and Good Conduct medal.
The Yeomen Warders are often incorrectly referred to as Yeomen of the Guard, which is actually a distinct corps of Royal Bodyguards.(Wikipedia)