The popularity of tomboys has sparked a sharp rise in the number of girls wanting to swap gender, according to a leading NHS psychologist.

New statistics show that for the first time, more than double the number of girls compared to boys seek the NHS's gender identity development service.

In popular culture, lead characters such as Katniss Everdeen in The Hunger Games, Tris Prior in the Divergent series, or Eleven in Stranger Things, have sparked a revival of strong tomboyoish, females.

In the past year there have been 1,400 'assigned at birth' females who have sought treatment, compared with 616 males.

"It's a very interesting question, and an important question, because it was the other way around initially," said Dr Polly Carmichael, who is the head of the gender identity development service.

"There have been different ideas put forward. Some people have talked about how it is easier for girls to cross-gender identify because it's a positive image to be a tomboy.

"People are also wondering what it is to be a female at the moment and whether that's something that is a cause for concern for young people."