dress currently consists of the same style high waisted blue-grey single-breasted jacket and white marcella shirt as men, a small bow tie and cummerbund and a straight ankle length blue-gray skirt, worn with patent-leather court shoes and barely-black tights or stockings. From the 1970s and prior to the introduction of current women's mess dress in 1996, female officers wore a royal blue "Empire line" dress made of crimplene material with a loose mandarin neck, long sleeves and an ankle length hem. Rank was indicated on a small enamelled brooch worn near the neck. Officers serving on Royal Auxiliary Air Force squadrons in Scotland may wear the Douglas Grey tartan with their mess dress. The RAF tartan was designed in 1988 and it was officially recognised by the Ministry of Defence in 2001. The tartan is worn by the RAF's voluntary pipes bands, although not as part of an official RAF uniform. RAF personnel without No 5 dress, such as airmen, junior officer cadets and some non-regular officers, wear No 1 dress with the blue shirt and tie replaced with a white shirt (not Marcella) and black bow tie should the need to wear mess dress arise. This dress pattern is officially designated Number 4 Dress and was previously known as (Interim) Mess Dress. Full dress In April 1920 Air Ministry Weekly Order 332 detailed a full dress uniform. It consisted of a single-breasted jacket in blue-grey with a stand-up collar. Rank was indicated in gold braid on the lower sleeve and white gloves were worn. Initially the full dress uniform was worn with the service dress cap. However, in 1921 a new form of head-dress was introduced. It was designed to resemble the original flying helmet and it consisted of a leather skull cap trimmed with black rabbit fur. The helmet also featured an ostrich feather plume which was connected at an RAF badge. This helmet was never popular and junior officers were eventually permitted to wear the service dress hat on full dress occasions. Group Captain the Duke of York (later King George VI) wore RAF full dress at his wedding to Lady Elizabeth Bowes-Lyon in 1923. The Duke wore or carried the full dress headgear rather than the service dress cap. The wearing of the full dress uniform was suspended just prior to the outbreak of World War II. Although the uniform was occasionally worn by air officers