The Children's Society has stepped up a campaign asking its supporters to lobby their local authorities to introduce policies to protect homeless young people.
The charity sent an email to 7,000 face-to-face donors last week, which links to a 90-second animated film called Mandy's Story.
It carries the message: "Every happy ending has a story. This one starts with you". It then plays the film and asks donors to sign up to its Safe and Sound lobbying campaign, launched last month.
Mandy's Story is based on actual events. It details how the charity helped Mandy to rebuild her life after she ran away aged 12 after her mother died. It tells how she escaped from a drugs-ridden squat when the police picked her up for shoplifting and asked social services to intervene.
Morag Stuart, head of one-to-one fundraising, said: "We hope these donors will engage with us and understand how important their donations are."