The UK Hip-Hop scene also known as Brit-Hop has been growing with the same speed as the US since the 80's. Although old school Brit-Hop emulated the US sound, by the 90's they veered off in their own direction. Experimenting with different sounds and flavors that produced sub-genres of music like Grime, Drum and Bass, and U.K.Garage. I've been to the U.K. numerous times and know cats that can spit with some of the best American MC's. They get busy over there and the big labels like Bad Boy, Def Jam and Interscope know it. That's why since the last few years they've been trolling the UK for talent.
Below are MC's Dizzee Rascal, Wiley, Klashnekoff and Sway. All from different parts of the U.K. and each with a different flavor. I linked their artist pages to the names if you want to know more about them.