ST THOMAS's, Norwich, has devised a spoof of the John Lewis Christmas advertisement. Instead of Monty the Penguin™, it shows a boy whose companion is an imaginary tiger. Fans of Calvin and Hobbes will recognise this metamorphosis of toy and imaginary companion. At the end of the St Thomas's ad, the boy responds to an invitation card and takes his tiger to church. The tiger is dropped as the boy walks towards an illuminated cross. (There is a glimpse of a second stuffed tiger, the significance of which escapes us.) The ad is well executed, and ought to attract more than the traditional card invitation. But why does it shy away from the rich Christian iconography: Christ the innocent baby, Christ the Good Shepherd? Call us sentimental, but in a world where no sparrow falls to the ground unheeded by God, we reckon that, for all its theological significance, an empty cross is a lesser embodiment of Christ's love to a young child than a valued soft toy.