The Christmas offensive has been waged well this year. The annunciation from the Church of England is that all ye faithful are coming to church, ecclesiastical pollsters are joyful and triumphant that so many believe in the Virgin Birth and clergy are urging that ’tis the season to bring an end to secular Christmas stamps. By all accounts the Christmas spirit has taken on a rather imperialistic flavour, but this isn’t the real message of Christmas says Jonathan Bartley