Quite enjoyed this glimpse of Heathrow past
+youtube+JOm7kdRPg!
It's a fine example of an airport that has successfully kicked out light aircraft activity.
I'm not old enough to remember light aircraft activity at Heathrow :)
In the case of Heathrow, which is operating at pretty much 100% capacity, I can kind of see why adding light aircraft to the mix might not be a sensible option.
Somewhere like Southampton however, which pretty much eradicated all traces of light aircraft a few years back, is a completely different deal.