Before I make a choice, I really need to understand what the OP means by "most terrible". In what way - worst dancer, most annoying??
Also, my definition of a 'joke contestant' differs wildly from the OP's. I think the joke contestant unintentionally started in Series 5 with Kate Garraway. She was clearly not hired to be such but, due to her sheer awfulness, it kind of evolved. And she happened to be with Anton who did everything to encourage her ...
The producers then hit upon something with Anton, foisting a succession of senior or overweight ladies who had zero chance of winning on him. The 'joke contestant' was well and truly born.
My joke contestant list would have read thus:
Series 5
Kate Garraway
Series 6
John Seargeant
Series 7
Lynda Bellingham
Jo Wood
Series 8
Ann Widdecombe
Series 9
Edwina Currie
Nancy Dell'Olio
Russell Grant
Series 10
Richard Arnold
Lisa Riley
Series 11
Tony Jacklin
Vanessa Feltz
Julien McDonald
Dave Myers
Series 12
Tim Wonnacott
Alison Hammond
Series 13
None
Series 14
Tameka Empson
I wholeheartedly agree with all those who say Mark Benton should not be in this list. Yes, he is overweight but he was quite a decent mover. After the advent of Kate Garraway, the joke contestant (in my eyes) is one who was hired to purely provide a comedy element to this entertainment show. That is to say, they could never win on their perceived dance ability but would be there to provide the laughs by ultimately & willingly embarrassing themselves.
The archetypal joke contestant became Ann Widdecombe. Like a few others, I actually liked her in the show because she threw herself into exactly what she was hired to do. All those bemoaning her zero attempt to learn to dance need to understand that that was never her motivation nor the producers reason for her signing up. I don't like her as a woman but it cannot be denied that she did tick that box and played it to the hilt.
Many here are naming people as 'joke contestants' in hindsight and for the wrong reasons. Craig Kelly, for example, wasn't hired as a joke contestant...he just became an arrogant big-head who thought he was better than he actually was. Quentin Wilson got
THE lowest score in Strictly history with 8 so he turned out to be perhaps the worst dancer ever even though I don't believe he was hired to be the joke in Series 2. To be a true' joke contestant', it needs to be seen from the outset that that is exactly why that celebrity is being hired.