Under Milk Wood
I think I still cannot adapt to the British accent yet, although the BEC test uses a British accent. Today I almost didn't could hardly understand the Welsh drama "Under Milk Wood", but I have found that to reciting poetry with a British accent seems the most beautiful to me. :)
Well... Welsh is not English, and the accents across all of the British Isles can vary so much that some speech is incomprehensible. Although Dylan Thomas wrote Under Milk Wood in English, he also threw in a lot of Welsh words that even native British people don't really know.
You've probably noticed there's a pleasant "skip" to British accents, which allows the speaker to speed up but still convery the important information (ie. count anything accented as important).
Search the phrase "Arthur the Rat", and you'll find the short story, read in a number of different accents. It's really nice to identify the differences.