Farnborough Air Show & Heathrow "Top Hat" airspace
 

I was at Saturday's FIA and before the Hornet or Red Arrows were due to display (can't remember which), the commentator mentioned that they had been approved "top hat" airspace from Heathrow. I guess this means that they wanted to reserve a chunk of London TMA higher than the Farnborough ATZ. I believe it was to 8,000 ft.

My question is really, what this does to the Heathrow inbounds and departures? From a controller point of view, would any arriving aircraft from Ockham on easterlies or departures turning south on westerlies be affected at all?

There was an AIP Supplement about procedures for Heathrow; can't remember the number.
It included Temporary Instrument Departures (TIDs) etc.

As Chevvron suggests, procedures are carefully laid down. There are temporary SIDs out of Heathrow to account for the change in airspace. Exactly what "Top Hat" means I have no idea but suspect its the commentator trying to sound clever!! (If I'm wrong then sorry).

Top hat refers to the shape of the airspace, a tall cylinder surrounded by a wider, shorter cylinder.

Er not quite Gonz, it refers to the 8nm radius RA(T) up to the base of controlled airspace topped by the 6nm radius Red Arrows airspace.

Yes, exactly, so it resembles the shape of a top hat.