I secured Lewmbit Opik as an after dinner speaker, when he was an MP and before he went into the jungle!
Had the chance to have a few Guinesses with him and he's a really nice bloke. Very knowledgeable about cars and knew all about Morgans. He drives a couple of really old tin tips with 6 figure mileage.
OK, maybe that doesn't top Ken Clark but he went up in my estimation hugely.