It is just as well that not many scraps are started at the Voller household in Sutton. By Christmas, all four family members could have achieved black belts.

The martial arts mastery began a year ago when Darcy Voller, then aged six, became the youngest girl in the world to be awarded a black belt at choi kwang-do.

The All Saints Benhilton Primary School pupil was taught by her expert father, Martin, 36, who runs a specialist academy in Banstead.

Now her mother, Kay, 39, and her older sister Karlyn, nine, are getting in on the act as they prepare to be graded for brown belts.

If they succeed next month, the family that fights together expects to be fastening four black belts together by December.

Martin said: “If a fight broke out at our home I would definitely get beaten up.

"I have to watch my back at the moment because my daughters can be a bit of a handful.

“Across the martial arts world, more and more teenagers are having success but eight or nine is usually the earliest age when someone grades as a black belt.

“As a father, I hope my daughters will never need to use their skills outside classes but it is a useful tool to have and helps them to develop confidence.”

In Choi kwang-do, practitioners strengthen muscles, tendons, ligaments and bones by using the maximum force of the body.

Darcy was graded in May 2008 by Grand Master Choi, who founded the scientific self-defence method to protect himself as a physically weak boy in war-ravaged South Korea.

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