The answer to the question of why the British have blonde hair lies in several biological, historical and cultural reasons.
Scientifically, hair colour is mainly determined by the pigment called melanin present in the hair. There are two types of melanin. One is eumelanin. This makes the hair black or brown.
The second is pheomelanin. Its action makes the hair lighter in color. Such as gold or red. Basically, blonde hair has more pheomelanin and less eumelanin.
This causes the hair to become lighter in colour. This can also be seen as a genetic trait. Which is more common in the northern and western regions of Europe.
Let us tell you that blonde hair is found especially in Northern Europe. It is believed that this genetic trait developed in humans during the last ice age.
In fact, in the cold and sunless climate of Northern Europe at that time, people needed more vitamin D, which the body got from sunlight.