Add to that one aircraft a minute leaving the holds or general vicinity of OCK, BIG, LAM & BNN to be at around 3,000 on a 10 mile final for Heathrow. There simply is no space for (uncontrolled) VFR above 2,500.
Ok debate started !
Heathrow inbounds normally drop to 4,000' initially droping to 3,000 close to the centre line and climb unrestricted to 6,000, normally at a very good rate. Only go-arounds climb to 3,000' (or 2,000')
Even Heathrow does not do 120 movements per hour.
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