Crisis is taking advantage of a grey area in the law to raise awareness of the challenges faced by homeless people trying to make a new start.
The campaign involves creating graffiti on walls and pavements by blasting water through a stencil. The water cleans part of the surface, leaving an image of a huddled homeless person made out of the words "Most homeless people have moved on but their problems haven't gone away". The image also carries the charity's website address.
Crisis has covered 15 public pavements, walls and other hard surfaces around the capital with the images. "The new graffiti technique is classed as a legal 'grey area' because cleaning rather than marking walls is not in itself illegal," says a spokeswoman for Crisis.
Crisis has chosen central sites, such as London's famous Abbey Road, to maximise the reach of the campaign. The images will remain in place for two months or until they fade.
"This campaign seeks to highlight that, though there are less visible signs of homelessness, the problem remains a major one," explains Andrew Page, director of fundraising at Crisis.
The campaign was created by marketing agency WWAV Rapp Collins London and is part of an initiative that will also target the national press and include blogs on websites such as MySpace and Facebook.