– Artillery and Paratroopers Black – Engineer Troops Yellow – Infantry and Infantry foot guards Royal blue – Cavalry and the Life Guards Light red – Anti-aircraft troops Black with yellow piping – Armoured Troops Green – Signal Troops Light blue – Service Troops Mess dress is a permitted uniform, in that it is allowed to be worn on defined occasions, but possession is not obligatory. There is always a corresponding form of obligatory uniform that may be worn as an alternative (army: m/87 A, navy: m/48, air force: m/87). Full mess dress is thus matched by högtidsdräkt (formal wear) and the lesser mess dress by sällskapsdräkt (society wear). Formal wear is the same as parade dress, when worn at the equivalent of a white tie occasion. "Society wear" is the service dress uniform, when worn to a black-tie occasion. Formal and society wear (rather than mess dress) are the mandatory uniform types for any military event, funeral, parade, state visit, or any other non-festive occasion. United Kingdom The Royal Household The officers of some ceremonial military corps, such as the Yeomen of the Guard and Gentlemen at Arms, are authorised to wear the evening dress of the Royal Household court uniform as a mess dress. Royal Navy The Royal Navy and some other navies distinguish between mess dress, which is now the equivalent of civilian white tie, and mess undress, which is the equivalent of black tie. Before 1939, there were three forms of evening dress: Ball dress (No. 2) – undress tailcoat, gold epaulettes, gold-laced trousers, white waistcoat, black bow tie, cocked hat Mess dress (No. 7) – mess jacket, gold-laced trousers, blue waistcoat, black bow tie, peaked cap. Mess undress (No. 8) – mess jacket, plain trousers, blue waistcoat, black bow tie, peaked cap. Today, there are only two forms of evening dress: Mess dress (No. 2A) – mess jacket, plain navy blue mess trousers, white waistcoat, black bow tie, peaked cap. Mess undress (No. 2B) – mess jacket, plain navy blue mess trousers, blue waistcoat or black cummerbund, black bow tie, peaked cap. Officers of the rank of captain and above wear gold-laced trousers (the gold lace stripes are nicknamed "lightning conductors"), and may wear the undress tailcoat (without epaulettes), with either mess dress or mess undress. The undress tailcoat is so named to distinguish it from the full dress tailcoat that was worn during the