A major artwork by Mark Wallinger and architects Studio Octopi has been launched in the English district of Runnymede, celebrating the legacy of Magna Carta.

Called Writ in Water, the architectural piece is a historic monument, remembering the time and place, over 800 years ago, that feudal barons forced King John to seal the charter – a founding moment in shaping the basis of common law across the world.

The 15.4m diameter circular building emerges from the hillside at the base of Cooper’s Hill, which is managed by the National Trust.

Built in cubits, the most ancient unit of measure, the walls are constructed of rammed stone from the site itself, with a dark stained softwood roof and crushed gravel floor.

Inside, visitors are led through a circular labyrinth into a central chamber, where the sky is visible through a wide oculus above a pool of water.

The shot blasted stainless steel sides of the pool are inscribed on the inner side, the water reflecting the reversed and inverted lettering of Magna Carta Clause 39 as the visitor moves round the pool to reveal its words.

Clause 39, Magna Carta:

“No free man shall be seized or imprisoned, or stripped of his rights or possessions, or outlawed or exiled, or deprived of his standing in any way, nor will we proceed with force against him, or send others to do so, except by the lawful judgment of his equals or by the law of the land."

Writ in Water takes its name from the inscription on John Keats’ gravestone.

According to Wallinger, the building reflects upon the founding principles of democracy, and “through a meeting of water, sky, and light, provides visitors with a space for reflection and contemplation.”

He said: “In common law, a writ is a formal written order issued by a court. In Writ in Water, the use of reflection to make the text legible plays against the idea of a law written in stone.

“Although Magna Carta established the law and the nascent principles of human rights, the United Kingdom has no written constitution. What seems like a birthright has to be learned over and over and made sense of. Whether the words are ephemeral or everlasting is up to us.”

The project was commissioned as part of the National Trust’s contemporary art programme, Trust New Art, which is inspired by its places.