Gonzo, i didnt mean that some authority should force anyone out, the airlines would choose to leave if there was a better more efficient london airport for their PAX - but not 'London' Oxford! (which is nearer to central birmingham - ridiculous!)
Give one of the other airports the new runway, if its needed at all, and improve the infrastructure and transport links to them and watch heathrow's problems disappear..
also, does anyone know why northolt is not developed for commercial short haul flights? airports THAT convenient for huge capital cities are valuable and all you see there are a few exec jets doing nothing. i drove past it twice a day for six months and only once saw something take off..