There are a multitude of options open to the modern rock star wishing to announce to the world that they have embarked on a new album. You can give interviews, allow webcams into your studio, offer a free download as a taster. Or you can appear on Andrew Marr's Sunday morning politics show in a feathered headdress, playing the autoharp over an incessant, off-key sample of the Four Lads' 1953 hit Istanbul (Not Constantinople), while a nonplussed Gordon Brown looks on….