Whistle Down the Wind is also a West End musical written by Andrew Lloyd Webber, based on a film.
In the film, set in Yorkshire, England in 1959, three kids find an escaped convict hiding in their father's barn. The eldest girl asks him who he is, and as he's in shock, he just exclaims "Jesus Christ!" The children take it a little too literally and think he's Jesus, risen again. They look after him and bring him food etc until they're eventually found out.
The theme song to the musical was released as a single, performed by the Australian singer Tina Arena.