 A particular variation is that used by mounted police in Merseyside which can be observed when they escort the winner of the annual Grand National horse race at Aintree; this consists of the traditional "Custodian helmet" with an added white plume and silvered chinstrap; along with the style of tunic it bears more resemblance to a late 19th/early 20th century police uniform.In the mid-1980s, "ceremonial blue" uniform and "ceremonial white" uniform were introduced in the United States Air Force.The ceremonial uniforms were discontinued by 1 August 1994 and 1 March 1993 respectively.