Fifty years of Doctor Who have proven one thing- this is an actor's show. All the special effects and skimpily dressed companions just wouldn't work if there wasn't a good leading man, and luckily, this series has had eleven (soon to be twelve- or is it thirteen?). But as much as this is a time for celebrating Messrs Hartnell to Smith, let's also spare a thought for the hundreds of guest stars who have crossed paths with the Time Lord. It can't be easy, finding yourself in the midst of alien worlds or alternative realities that mean everything to the baying hordes of fans but nothing to you, a mere jobbing actor. In spite of that, many have risen to the challenge magnificently. Others looked as though they're reading from cue cards. Some were just downright bad. And then there were a few, a precious few, who were good and bad and all points in between. This type of actor can pout, leer and cringe all at the same time. This type of actor has problems controlling his or her indoor voice. The type of actor sees a fibre-glass monster head and thinks 'screw the Method, I'm hamming this one up'. You see, any fool can act. It takes a very special type of actor to go completely and utterly over-the-top. These guys knew that: