The helicopter had been static over what was probably Marble Arch for a while, throbbing, but as still as a fly on a great white wall. Then it came about, it's forward tilt and livid buzzing filling the park and bouncing off the towering green panels. The units of lunching workers, sun-bathers, exercisers and personal trainers seemed at the very least unperturbed, if not unaware.

It repeated this display for about an hour, drawing back with a disinterested feign in it's tail and a quieting of it's chopping, before again galloping nearer, the buzz and beating undulating lower and the drone becoming a coarse, thudding rattle.

Somewhere over in the lower-east part of the park, a segment of panels receded whilst in the upper east a few drew inwards by a few inches. A group of people clad head to toe in green bodysuits that unloaded from a sleek truck of the same colour, converged on a shapely hillock and seemed to stand in deliberation, silhouetted against the vivid blue of the sky. But from this far away nothing could be heard.

Upon exiting, it was only just noticeable that the corridors during the last weeks now led out on to a different length of Piccadilly. The previous location, though technically in the eyeline along the great boulevard, was too far away and had become engulfed in mist. Above, the billowing clouds towered fantastically like heavenly kingdoms painted on the ceiling of a great chapel. The smell of solvent was strong.