Good evening all...

How many really noticed the differences in the tail fin flash on British Aircraft during the First and Second World Wars?
The roundel was adopted because the Union Flag only showed up as a cross at distance, thus being confused with the German Maltese Cross in the First World War. The French had already adopted the roundel as a stylised version of the revolutionary cockade of Napoleonic times. The British simply reversed the colour of the circles to blue outer and red inner. Intriguingly, the tail was painted with blue white and red vertical stripes on BOTH French and British WW1 aircraft, and reversed to red, white and blue for the RAF in WW2.
Many aircraft modellers (and some replicas) make the mistake of having incorrect fin flashes for WW1 aircraft.
To avoid similar confusion, in WW2 the RAF roundels in the Far East dropped the red inner circle to avoid it being mistaken for the Japanese Rising Sun symbol.