"My chances of being PM are about as good as the chances of finding Elvis on Mars, or my being reincarnated as an olive"

This quote by Boris Johnson is a humorous way of revealing his uncertainty in becoming Prime Minister. He is comparing his possibilities of ending up being Prime Minister to 2 extremely not likely situations: discovering Elvis on Mars and being reincarnated as an olive. By making these contrasts, Johnson is suggesting that his possibilities of becoming Prime Minister are slim to none. This quote likewise serves as a pointer that Johnson is a humorous and easy going politician, which is a trait that lots of people appreciate. Johnson's quote is a creative way of expressing his uncertainty in becoming Prime Minister while still preserving a funny bone.