The above photo was a happy accident.
A few weeks back I was scouting canal locations for a fashion shoot. Towards the end of the day I found myself following the slow twists and turns of the Regents Canal, heading west towards Maida Vale. As soon as I entered this particular tunnel I spotted the mysterious figures up ahead. Only a few seconds remained before they reached open air. I sensed an opportunity... Quickly I lifted my camera and fired off a shot, still moving as I did so. Amazingly, the darkness of the tunnel balanced the brightness of the water's reflection, and my camera's autoexposure algorithms landed square in the middle to deliver a perfect exposure.
A second later, the moment had passed.