Possible Clues:

• Having nodded off
• Having dropped off first of letters in a leak
• Disturb please — on the contrary for kipper's state!
• Nineteenth-century PM's a revolutionary without feeling
• See pal slipping into the land of nod
• Could it be Wayne is not paying attention?
• … has gone off
• Dreaming, perhaps
• Napping, the general is swallowed by snake
• Comatose snake encircling shelter