4 Cowley Street

Tucked beneath the elegant façade of the former Liberal Democrats’ headquarters at 4 Cowley Street, Westminster, lies a truly extraordinary transformation by Aquascapes. This Grade II listed London landmark has been reimagined with a bespoke subterranean leisure suite, seamlessly blending architectural heritage with modern indulgence.

The once-unused basement has been masterfully converted into an exclusive pool, spa, sauna, and steam room — a private sanctuary of wellness and sophistication in the heart of the city.

At the centre of this luxurious retreat is a 9.5-metre pool, accompanied by a connected spa, both illuminated by underwater LED lighting that accentuates the tranquil ambiance. The steam room, wrapped in a rich palette of dark glass mosaics, exudes elegance, its curved seating offering both comfort and style. Adjacent to it, a custom-built sauna crafted from ceramic and fine Hemlock Spruce, heated by volcanic stones, creates the perfect contrast of warmth and texture.

Basement conversions in London often come with challenges — from limited natural light to strict heritage constraints — yet Aquascapes’ expertise in innovative lighting design and specialist construction techniques ensured every detail was executed flawlessly. The result: a stunning, light-balanced environment that preserves the building’s structural integrity while delivering an unmistakably contemporary finish.

From concept to completion, Aquascapes managed every element of design and construction with precision and care. The outcome is a remarkable fusion of heritage and modern luxury — a timeless, hidden gem beneath one of Westminster’s most distinguished addresses.