24 March 2021 marks the centenary of the birth of the Royal Air Force Ensign. 

There are a few types of flags within the RAF, such as the one and only RAF Colour; the Squadron Standards; the Ensign seen at RAF bases and Command Flags used by senior officers. 

We can trace the history of Ensign back to the English Fleets’ flags. Back in 1558, there were three Royal Navy fleet units known as the Red Squadron, the Blue Squadron and the White Squadron, each flying their own colour Ensigns on vessels. The Red Squadron patrolled the Atlantics, the Blue in the Pacifics and the White near the English Channel. The colours were also featured prominently wherever the Squadrons went; hence the Red Ensign of Canada, Blue Ensign of the old Colonial Hong Kong, the Blue Ensign elements on the Australian and New Zealand national flags. In 1864 the three coloured Squadrons was dissolved and the White Ensign was adopted by the Royal Navy, Blue Ensign since then was used for public services vessels and the Auxiliary Navy fleets, while the Red Ensign is being used by the Merchants Navy and civilian vessels.  

For the Royal Air Force, which was created from the Royal Naval Air Service and Army’s Royal Flying Corps, there were no flags or heritage for the newly established air force to rally to. One reason that it took them 4 years to get an official Ensign was because the Admiralty could veto any flag designs flying at sea and on British soil. 

One initial design the Air Council submitted was the White Ensign without the red St. George’s Cross. It resembled the Royal Navy’s White Ensign and the Admiralty reckoned that any White Ensign shall be reserved for the RN. 

Another design was to use a Union Jack with white border. That was also banned by the Admiralty because the same design has been used by the Navy to signal for a pilot (nautical pilot, not aviation pilot). 

Later with design ideas gathered from the public, the Roundel was incorporated into the new RAF Ensign design, despite it was also used by navy and army aircrafts. The RAF Ensign has the Union Flag in the carton, the British roundel in the fly and a light blue field as the background, unique to all naval Ensigns. 

This design was then brought to the Admiralty and King Geroge V for approval. On 24 March 1921, it was officially recognised as the Ensign for the Royal Air Force. 

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【皇家空軍 Ensign 創立百年】

剛過去的三月廿四日是皇家空軍旗幟 Royal Air Force Ensign 創立一百周年。

皇家空軍的軍旗有多種，例如： 空軍最高級的 Colour 、中隊用的Standard、在基地常用的 Ensign、軍官用的Command Flag 等等。

Ensign 歷史源自海軍艦隊。在 1558 年，英國海軍分為 紅、 藍、 白 三個艦隊 (Coloured Squadrons)，每個艦隊用各自的顏色旗代表，這便是最早期Ensign 艦旗的由來。 Red Squadron 巡航於大西洋，Blue Squadron 於太平洋，White Squadron 於英國近本土水域。而由艦隊登陸的屬土亦以其艦旗顏色代表，加以改良成為地方旗幟 - 例如舊加拿大的Red Ensign 和舊香港的 Blue Ensign、澳洲和紐西蘭國旗等。後來皇家海軍於 1864 年改組，取消了三色艦隊，而亦改於所有海軍艦隻用上白艦旗 White Ensign；藍艦旗 Blue Ensign 由輔助海軍使用；紅艦旗 Red Ensign由商船使用。

至於皇家空軍的Ensign，要到空軍成立後四年才被認可。1917年新成立的皇家空軍是新軍種，未有自己的旗幟代表，將領們希望以全新的空軍Ensign高掛於空軍基地。但因為原來英國海上及陸上的所有新旗幟都要經由 Admiralty 海軍部批核，Air Council 空軍議會（後來變成 Air Ministry 空軍部旗下的Air Force Board）提出的旗幟設計都被海軍部否決。

當時最初空軍議會希望使用  和海軍 White Ensign 近似的白色設計，減去中間的 Saint George's Cross 紅色聖佐治十字；但海軍當然否決，認為White Ensign應只由海軍使用。空軍議會的第二個提意是用配有白邊的Union Jack，但亦被海軍部否決，因為跟海軍的訊號旗 Pilot Jack 領航員旗（Pilot 指領港/領航員） 相似。

最後空軍部希望把用在飛機上的 Roundle 圓徽放入Ensign 的設計（雖然海軍和陸軍的飛機都採用相同的圓徽），並交給了 海軍部 和 英皇佐治五 批准，最後於 1921年 3月 24日正式獲認可為皇家空軍的 Ensign 旗幟，可於皇家空軍基地高掛。