Orbiting right now at 27,000 ft over the start of the London Marathon, for TV coverage is French King Air 200 F-HFRF of operator Aero Sotravia. Doing this has them in direct contact with all the various camera positions round the course, and they then downlink the signals to a central point. I first noticed this approach in the London Olympics Marathon in 2012, again with a King Air, which was orbiting at altitude over Lambourne VOR during the race.
However, a French operator for the London Marathon ? Can you honestly see the Paris Marathon chartering in a UK operator ?
AS-355 G-INTV is doing the low level pictures underneath it at 1,700 ft. Notably, from just a couple of miles away across the river Thames, the King Air's PT6s are more audible than the chopper.