A tale about a family trapped in a nightmare could make a child author’s sister’s dreams come true.

Nine-year-old Teagan Jacobs has had her story Terrified published and is donating all the proceeds towards funding her little sister Mia’s bid to compete in the BMX World Championships next year.

The 22-page story, which the family has self-published, sold out the first 100 copies in less than 48 hours. A further 600 have been ordered.

Written when Teagan was eight, the story tells of a family trapped inside a school girl’s nightmare and has been illustrated by artist Megan McCormick.

In response to the success the Raynes Park girl has decided she wants the book to help fund her sister’s bid to raise at least £5,000 to compete abroad next year.

The pair, who both attend Hollymount Primary School, Raynes Park, are avid BMX enthusiasts and compete for Peckham Challengers club.

While Teagan narrowly missed out on qualifying for the World Championships, Mia, eight, collected enough points throughout the season to be selected to represent Great Britain.

Their mother Charley Hardy said: “Raising money for Mia was all Teagan’s idea. She came home from school one day and said I’ve done something an I don’t know if it was right.

“Of course I’m immediately thinking oh no what’s coming and she said she’s started selling her book and they all want one.

“She just said she wanted the money to help Mia. The next day parents were coming up to me saying could they buy a copy so I rushed home and researched getting it published “They are both real dare- devils – if you tried to get them to do ballet they would run away.”

Miss Hardy, who has just started work as a nanny, said she and the girl’s father Leon Jacobs, an HGV driver, are desperately trying to save in order to allow Mia to compete, but expect they will need a minimum of £5,000 for the 10-day trip to South Carolina for the family, which also includes 17-month-old Kimmy.

To help promote the book, which can be bought for £5.99, or as an e-book for £3.99, Teagan will be at Wimbledon Library on October 28 from 2.30pm to 3.30pm and at Raynes Park Library from 11am to 12.30pm on October 29.

Miss Hardy added that she was hopeful of securing a slot during half-term at Waterstones in Putney and also at the 24-hour Raynes Park Tesco.

To buy a copy of Terrified visit www.blurb.com or to help Mia’s fund-raising visit gofundme.com/getmiatoamerica.