ESPA Life at Corinthia is now one of London's largest spas, yet sensitive, smart light design means that guests experience it as a cosy, calm, private world.

Atmospheric functionality peaks in the sub-basement, where Ellie Greisen of Lighting Design International staged a stunning light scene in the black marble pool room. 

The light which is cast up from the bottom of the stainless steel pool passes through ever-moving water, creating dynamic patterns on the white ceiling while illuminating the entire room.

Colour-changing, dimmable fittings were used to precisely define the steps and to illuminate the feature wall of gold-veined black Tunisian marble.

'The whole feeling is really relaxed,' says Ms. Greisen. 'It's like another world.'

'There's an 'infinity' ripple over the pool edge,' she says. 'We didn't want this to be a trip hazard as this room is supposed to be mostly dark, so we concealed side-emitting fibres below the waterline around the edge. It creates a nice glow.'

'We wanted to light evenly across the whole ceiling, not just at the edge. So it had to be flush fittings across the bottom of the pool that people can comfortably walk on.'

'When designing light, you're thinking all the time about how someone will feel when they are there. That's what you try to understand. You want an overall feeling and effect, but it must always be functional too.'