Heathrow - There are the helicopter routes over the Thames and then there's a SVFR clearance over Ascot, right? But as far as I know, there is no way of transitioning anywhere else. I could be wrong - it's been a while since I flew in London.
My point being is that by stepping down to a less restrictive airspace generally, transitions can be achieved anywhere and/or when traffic permits. This helps everyone, even IFR traffic.
Last edited by AdamFrisch; 31st Aug 2012 at 14:50.