Contractors working on the refurbishment of CoDE The Court, a former courthouse turned hotel, made an unexpected discovery in the building’s attic: a rare Crossley four-stroke gas engine, believed to be the second-oldest of its kind in the world and the oldest surviving example in Europe.

Originally installed in the short-lived “Royal Aquarium” at Waverley Market in the late 19th century, the engine was later relocated to the former Edinburgh police chambers in 1881, where it served a crucial role in powering the building’s ventilation system.

The discovery was made during internal renovations led by CoDE Concepts. What started as a routine redevelopment took a dramatic turn when the construction team stumbled upon the machinery concealed beneath decades of dust and neglect. A photograph posted online triggered a flood of expert responses, quickly identifying the engine’s historical and mechanical significance.

“This is one of Scotland’s most remarkable finds in recent memory,” said Andrew Landsburgh, director of CoDE Concepts. “Our renovation uncovered not just a forgotten piece of industrial machinery, but a direct link to the country’s engineering heritage.”

The engine has since been carefully removed from the attic and installed in The Lost Close—a set of historic underground vaults rediscovered during earlier renovation phases in 2019. Now open to the public, this heritage feature forms part of CoDE’s new Scottish Innovations Tour, launching in June, which highlights Edinburgh’s contributions to global industrial advancement.

“This find demonstrates the value of sensitive refurbishment in historic buildings,” Landsburgh added. “It’s a powerful reminder that the built environment can still hold secrets—especially in a city as layered as Edinburgh.”

The story of the discovery will be featured in Potential Energy, a documentary premiering at the Scottish Storytelling Centre on May 23.

With only two other comparable engines known to exist, one housed at the Henry Ford Museum in Michigan and another in Denmark, the Edinburgh find represents a rare survival of early industrial technology. Its preservation and integration into the newly developed heritage tour offer a compelling case study for construction professionals balancing redevelopment with cultural conservation.