You see absolutely loads of these around Oxford and Reading, and they're starting to become a problem because people are feeding them and they're becoming bold enough to steal food out of people's hands (like seagulls) (sorry, that's not good news).
Kites from Spain were introduced to the Chiltern Hills back in the 90s when there were only 52 breeding pairs in Wales for the whole of the UK. Thirty years later there's 4000 breeding pairs in southern England alone and red kite chicks were being sent back to Spain to help with their numbers.