Yeah, was just about to say the same thing as KFDancer.
You'll be looking at several grand to ship the car and to get it converted so that it's road legal in the UK... so unless your car is rare or vintage, and you'll never get another one like it, then it's probably not worth trying to ship it. It would likely be cheaper to sell it and buy a car in the UK (i.e. used cars here are much cheaper than used cars in the US)
On top of that, parts will be expensive and the insurance for an imported car is likely to be through the roof ... not just because it's imported, but also because if you don't have any UK driving history, the insurance is likely to be higher anyway.
My brother once bought an imported car from eBay UK, but then he discovered his insurance was going to be £2,000 a year instead of about £500 (and he's British and had a few years of UK driving history under his belt), so he immediately cancelled the sale and bought a 'local' car instead, which was much cheaper to buy, insure and repair.