TWO sisters from Herefordshire are set to be the youngest ever contestants on Dragons' Den when the television programme airs on Sunday evening.

Twelve years old Sky Ballantyne and her 14-years-old sister Kia, who live in Ross-on-Wye, will be promoting their invention the Crikey Bikey harness, which is designed to help adults teach their children to ride a bicycle without hurting their backs.

The pair are pupils at the independent Haberdashers' Monmouth School for Girls and Sky came up with the idea last year as part of a school homework project, having watched a father struggle to hold on to his child's bicycle. Within 18 months she had not only won a school competition with her invention, but won a best in show award in the Big Bang competition, set up a company with her sister Kia to sell the harnesses, applied for a patent, sourced a manufacturer and received orders from retail giants Evans Cycles and Mountain Warehouse.

The sisters have been advised by their father Floyd, who is a business trainer, and mother Ali, a history and geography teacher, plus family friend Jeremy Wilson, but the invention and business foundations have been all their own work.

Sky said: "We were in the Den for almost an hour and a half. Although the questioning was tense, we both really enjoyed it. I felt really happy when Sarah Wellingham said that if her children grew up to be like us then she would be really proud."

The Ballantyne sisters' appearance on Dragons' Den will be broadcast at 8pm on BBC Two on Sunday, September 6