Dan Nolan was last seen on New Year's Day this year when he went on a night fishing trip with friends on a pontoon in Hamble Village, near Southampton, Hampshire.
The family of the 15-year-old has received no news of him since. Despite widespread searches and the offer of a pound;50,000 reward, no evidence has been found to indicate that he drowned or was abducted.
Last week his parents, Pauline and Greg, faced an emotional wait after police told them that a young person's corpse had been discovered on Yately Heath near Fleet in Hampshire.
The body later turned out to be that of another missing teenager, 13-year-old Milly Dowler.
Mrs Nolan, 45, said: "When I had the call from the police saying it was not Dan, I went through so many emotions. It is the not knowing that is awful. Because we do not have bad news we are still hanging on to the hope he will appear safe and well. But - and I know it is a nasty thing to say - bodies do turn up."
Before Dan's disappearance Mrs Nolan worked as a learning support assistant for pupils with emotional and behavioural difficulties at Brookfield community school in Sarisbury Green. She has recently set up a charity called Mateminders, which encourages teenagers to stick with their friends when they are out and about.
Mark Wheeller, a teacher at Oaklands community school, Southampton, has written a play about Dan for the campaign, which recreates the night he disappeared and the events which followed.
The play will receive its first performance in November and will tour schools next year (2003). It is titled Dan Nolan (one laugh) missing after a comment a friend made about missing Dan's laughter.
Mateminders plans to follow the play with an educational video and CD-Rom.
Mrs Nolan admits that her underlying motive for the campaign is that it may lead to someone coming forward with new evidence about her son.
But she believes that its simple message - that young people should not walk home alone - could prevent others from disappearing.
She said: "Dan went missing after he got separated from his friends. If Milly had walked home with a friend, it could have been different for her, too. The chances of a child being abducted are very, very slim, but I think the world is crueller and more evil now."
Miss Nolan visited Dan's school, King Edward VI in Southampton, this week as it marked its 450th anniversary by attempting a world record for the biggest-ever chorus line with more than a thousand dancing teachers and pupils.
History teacher Shona Noble said the independent school hoped the event would remind the public that one of their pupils remained missing. "Dan is still on the school register," she said.
A spokeswoman for Hampshire police said the search for Dan continued and that officers had no new leads.
She said: "This is still a missing person case. We have made repeated searches, including a major search underwater, but have no new lines of inquiry."
For details visit www.dan-nolan.co.uk. For play visits or scripts, email firstname.lastname@example.org. Anyone with information about Dan's disappearance should call 023 8045 2207