The UK sure loves speculation about prime ministers. So here’s some more! But who makes the finest – Stephen Fry, Emma Thompson, Jane Horrocks or Alan B’Stard? As the UK gets ready to have its seventh prime minister in 10 years, how long before a revolving door is installed at 10 Downing Street? As social media wags have pointed out, this is likely the first time in history that the UK has been l…