The national press and television took a break from the political party conferences last month to pursue the growing mystery of carved stone heads, more and more of which appeared in Yorkshire throughout September and into October.

And the press interest did not stop at the shores of the UK. Even international press and a variety of websites - both mainstream and otherwise (Ghosts Among Us?) - picked up the story.

The mystery heightened, then focused in on a Yorkshire stone carver, Billy Johnson, and a company called One to One Productions who had produced a website for him.

One to One have a website of their own exploring hypnagogia, the state half way between being asleep and awake. It is in this state that the faces Billy carves can apparently appear to him.

Judy Alston, a director of One to One, initially told NSS that Billy was "a bit of a recluse" with neither land line nor mobile telephones and no television. She thought he was away on holiday in Scotland or Ireland. She said people who had received his heads were lucky as they usually sell for around £350 each.

Eventually One to One claimed responsibility for the appearance of the heads, saying they had worked with Billy to leave nearly 50 of them as part of a multimedia art project.

Judi Alston said: "Our original intention was to use feedback and stories generated by this experiment to develop into a digital media project. We are working with Billy to explore ways of integrating mythology, modern folklore and traditional craft skills such as stone carving with new media and web-based technology to produce innovative, creative work that can be freely accessed."