Region codes were developed as titles are released in different parts of the world at different times, solely for market reasons. But even without region codes, there is another problem. Standards compatibility. There are two major standards used throughout the world (although a number of variations of each). Those are NTSC and PAL. (SECAM is a close cousin of PAL.)
NTSC operates on a 30 frame rate while PAL runs on a 25 frame rate. With the old CRT TV sets, that pretty much precluded either one from ever operating on the other. Newer LCD/Plasma technology allows for multiple frame rates and COULD adapt between the two standards. (It's not limitless and your manual will specify the limitations of your set.)
But even if you could overcome the frame rate incompatibility, there is still the color standard and there is not Rosetta Stone built into TV sets for that. Trying to watch a PAL video on an NTSC TV will, at the very best, provide a pathetic, distorted black and white image, and the same is true in the opposite situation.
North America (US, Canada, Mexico) uses the NTSC standard, while the UK and most of Europe uses the PAL standard. Bottom line, you're screwed, region code or no region code.
One possible fix: If you are willing to spend the money on good DVD copying software (and personally, to me, the only GOOD one is AnyDVD), as well as decent DVD burning software, then that software can decode the the PAL standard and frame rate, re-encode it to NTSC, and burn a DVD that will play for your TV. The quality may not be perfect, but it will be eminently watchable with little complaint.