Meanwhile, in an isolated corner of Wimbledon Common

Tobermory stiffened for a moment beneath his ghillie suit before willing his muscles to relax. With a single slow, fluid, practiced move he flicked the safety off his Barratt .50 calibre rifle and chambered a huge steel-jacketed round - capable of firing clean through an engine block.
He controlled his breathing. Slowly in and out, waiting, watching through the scope down through the trees and undergrowth. Perfectly still now but for a whitening of his knuckles on the grip and a rhythmic twitch of his left eyelid.
"Go ahead", he muttered to himself. "Drop the can. Do it. Drop the can. Drop. The. Can."