The mother of the teenager abducted by Petts Wood man Jeremy Forrest is writing a book on the ordeal.

'Runaway Schoolgirl' will document the anguish she suffered after finding out her daughter had run away with the former maths teacher, according to a national newspaper.

It is said the book is due out next February, preceding Forrest's release from prison by a matter of months.

Now 31, Forrest is currently serving five-and-a-half years behind bars for abduction and sex offences after fleeing with the 15 year-old to France in 2012. 

Forrest worked at Bishop Justus School in Bromley Common before moving to a job in Sussex, where he met the schoolgirl. 

The author, who said she felt like "the world's worst mum" during the trial, and her daughter cannot be named for legal reasons.