The Herald has recently launched a competition aimed at inspiring young writers.

Open to children aged five to 17, The Herald Children's Story Writing Competition is run in conjunction with Turnberry Resort in Ayrshire and Scottish Book Trust (full competition details below). It offers some tantalising prizes, but as most authors will tell you, they are not in it for the money – which is just as well, because few make a fortune. The satisfaction and pleasure it brings are enough.

Lest anyone think that primary-age children are too young to consider fiction, think again. Alexander McCall Smith first sat down to write a book when he was nine. "It had the wonderful title He's Gone," he recalled recently, "though where he went or what happened -"

Could anyone have predicted from this early work the astonishing literary career that lay ahead? It's unlikely. Lots of children, who never go on to write for a living, love making up stories. I doubt there's a time when imaginations are more fertile and unfettered than in the years before self-consciousness cramps the style.

One day a boy called Thomas arrived on McCall Smith's doorstep with his mother. He handed the famous writer a novel he'd written and asked if he would read it. "It was called The Great Toffee Theft," said McCall Smith, "and it went: 'There was a man and he stole all the toffee. The police came and took him to jail. The End.' So I felt he really should have gone to Ian Rankin, two doors down."

Some time later Thomas, who is seven or eight, returned with a longer work (what McCall Smith calls his magnum opus). Putting on his spectacles, McCall Smith read some of it to me. Called Larry And Dave, it began with chapter nought: "One day Larry said to Dave, 'Should we get a new cat, because our old cat died?' 'OK,' said Dave -"

They get a cat, which accompanies Dave to his drum lessons. Fast forward to chapter eight: "One afternoon cat was playing with his rocket – 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, blast-off – when the bell rang. Cat ran to the door. Scottish Gas was there."

Isn't that terrific? Great characters, lots of action and punchy dialogue. Already, Thomas has mastered the essentials of the trade.

The Herald Children's Story Writing Competition is certainly not intended as a short cut for talent scouts hunting down the next McCall Smith or Zadie Smith. Its aim is purely recreational, as all creative writing at school age should be. If it prompts a child to read more or write better, then that's a bonus. But first and foremost, writing should be about enjoyment. It can be a tortuous process, but it is also addictive and surprisingly fulfilling. So, if you know anyone who might enjoy taking part, the guidelines are below. And if Thomas or his family are reading this, please write another story and send it to us.

The Herald's Children's Story Writing Competition has three categories: writers aged five-eight (100-500 words), nine-12 (500-800 words), and 13-17 (up to 1000 words). There are three story titles to choose from – The Holiday Secret, Strangers In Town and New Beginnings – and the prizes will be judged by a panel of five, comprising children's writers, illustrators and book specialists, including novelist Elizabeth Wein, illustrator David Roberts and myself.

There will be one winner for each age category, and an overall grand prize winner, who claims a Google Nexus 7 tablet, a family visit for up to six people for three nights at Lands of Turnberry Self Catering Apartments, £500 Scottish Book Trust book vouchers and a Turnberry goodie bag. The two runners-up win a Kindle Fire, £250 Scottish Book Trust Vouchers and a Turnberry goodie bag.

The closing date is January 14, 2013. Entries should be sent to: Children's Story Writing Competition, The Herald Marketing Department, 200 Renfield Street, Glasgow G2 3QB. Please state age and theme on the envelope. The winner will be announced in April 2013 at an event held at Turnberry.