Townson began her writing career with Punch magazine, for which she was a regular contributor for many years. The magazine invited her to write reviews of children's books, which would eventually lead to her writing her own material.

She also worked as Chief Assistant Librarian for part of Greater Manchester, a role that included responsibility for libraries in 110 schools, eleven public children's libraries, and four colleges.

Her first book, entitled Looking for Lossie, was published in 1975.

As of 1998, Townson published books totalled 55. These ranged from picture books to teenage novels.

Some of Townson's books, such as The Speckled Panic and Terrible Tuesday, have been adapted for television. She has also had stories commissioned for Granada Television's Time for a Story, Tickle on the Tum and Story World programmes.

She frequently visits schools, libraries, colleges and writers' groups to talk about children's literature and to assist with creative writing.

Since its formation in 1985, Townson has chaired the panel for the annual "Lancashire Children's Book of the Year" award.

Richard Branson printed 500,000 copies of Townson's Adventures of a Lottery Winner to give away to youngsters on his Virgin Atlantic airline. Bury Metropolitan Borough Council

Born in Nelson, Lancashire, Townson was brought up in the Pendle valley. She attended Accrington High School and then studied English at the University of Leeds.

The Lenny and Jake series

• The Great Ice-Cream Crime (1981)
• The Siege of Cobb Street School (1983)
• The Vanishing Gran (1983)
• Haunted Ivy (1984)
• The Crimson Crescent (1986)
• The Staggering Snowman (1987)
• Fireworks Galore! (1988)
• Walnut Whirl (1989)
• Hopping Mad (1991)
• The Kidnap Report (1992)
• A Night on Smugglers' Island (1993)
• The Sign of the Crab (1994)
• Cats and Burglars (1995)
• The Clue of the Missing Cufflink (1996)
• Trouble on the Train (1997)

Tiger Young Readers' Series

• Through the Witch's Window (1989)
• Amos Shrike, the School Ghost (1990)
• Snakes Alive (1991)
• Blue Magic (1992)

The Speckled Panic Series

• The Speckled Panic (1982)
• The Choking Peril (1985)
• Hot Stuff (1991)
• The One-Day Millionaires (1995)
• Coughdrop Calamity (1995)

Picture books

• What on Earth...?
• Terrible Tuesday

Other titles

• Pilkie's Progress (1988)
• Who's Afraid of the Evil Eye (1994)
• The Moving Statue
• The Deathwood Letters (2003)
• The Secret of Celia
• Two Weird Weeks (2003)
• Disaster Bag
• Rumpus on the Roof
• Trouble Doubled
• The Peckthorn Monster
• The Shrieking Face
• Your Dad, My Mum (2001)
• Ignorance is Bliss (2001)
• Invisible Boy (2002)
• Diamond Hunt (2003)
• The Adventures of a Lottery Winner (2004)
• Shots in the Dark (2004)
• The Secret Room (2004)
• Danny - Don't Jump (2005)
• Snakes Alive! and Other Stories (2005)
• Dark Deeds at Deathwood: Deathwood Letters 2 (2006)
• Vanishing Village (2007)
• Deathwood Damian Strikes Again (2008)