Not denying it, but it does depend on what you're sending.
For example, if you send something by DHL, it has a significantly greater chance of going through East Midlands Airport than it does Heathrow.
Same for UPS and others. The bulk of their recent investments have been away from Heathrow.
The non-Heathrow sites have better road connections, and more importantly for air cargo, the noise abatement rules at non-Heathrow sites are more relaxed.
The other problem with Heathrow is that BA have their finger in the pies and they have too many slots, so that limits any growth on the independent freight side.
Heathrow has effectively hit its capacity limit. That may or may not change if they ever build the third runway.
