Purple is the rarest colour on national flags. In fact, of the 196 countries of the world, virtually none of them use purple on their national flag. However, a small number of nations have amended or changed their national flags over the years to feature very small portions of purple. For example, the Second Republic of Spain (1931-1939) featured purple as part of their tricolour design, whilst Nicaragua added purple to the triangular design in the very centre of their flag in 1908, and Dominica included purple within an image of a bird in 1967.

Not only does purple feature very rarely on flags today, it was never used to represent a Kingdom or country before the 20th Century. But, there’s a very simple explanation why; purple was once the most expensive colour to produce. In fact, until the 1800s, purple dye was worth more than its weight in gold. Just 1lb of purple dye was once worth $56,000 (£46,421) in today's money.

This is because the dye used to make purple originally came from a sea snail only found in a small region of the Mediterranean in what is now Lebanon. A lot of work went into creating purple dye and over 10,000 sea snails were required to produce just 1 gram of purple dye. Quite often, this price was too steep even for royalty!

In short, purple dye was just too expensive to use on national flags. Not even the richest nations could justify the cost of having purple on their flags.Not only does purple feature very rarely on flags today, it was never used to represent a Kingdom or country before the 20th Century. But, there’s a very simple explanation why; purple was once the most expensive colour to produce. In fact, until the 1800s, purple dye was worth more than its weight in gold. Just 1lb of purple dye was once worth $56,000 (£46,421) in today's money.

This is because the dye used to make purple originally came from a sea snail only found in a small region of the Mediterranean in what is now Lebanon. A lot of work went into creating purple dye and over 10,000 sea snails were required to produce just 1 gram of purple dye. Quite often, this price was too steep even for royalty!

In short, purple dye was just too expensive to use on national flags. Not even the richest nations could justify the cost of having purple on their flags.