Archaeologist stunned to find remains of medieval castle hidden in dingy corridor under Chester Crown Court

Archaeologists discovered an 800-year-old part of a medieval castle beneath Chester Crown Court and made the discovery using little more than light from a smartphone.

Researchers say the discovery was made by an expert observing the stonework at the end of a dark, gloomy corridor beneath the courtyard. When archaeologist Stewart Ainsworth lifted his phone to illuminate the corridor, he encountered something surprising: a sudden change in the masonry.

“With the light from my phone, I could immediately tell that in the darkness in front of me, a large section of the wall was completely different,” said Dr Ainsworth, from the University of Chester.

“It turned at a steep angle and disappeared, leaving a very dark, narrow space that I couldn’t fit into.”

As researchers compared the stones and construction technique with surviving parts of the Norman castle, they became confident that parts of the underground wall dated from the medieval period rather than the 18th century, when architect Thomas Harrison built much of the current prison and court complex.

Chester Castle’s medieval defenses had apparently survived centuries of hiding inside the new structure.

“But the wall I discovered is huge (almost three meters high) so we now know that much of the medieval stonework was left untouched,” Dr Ainsworth said, referring to later builders. “And I’m guessing many more could survive underneath the parking lot and castle complex.”

Archaeologists then used digital scanners to locate the underground wall. By comparing old maps and plans, they found that it was part of a bridge built about 800 years ago.

According to researchers, the bridge crossed a deep moat surrounding the castle’s heavily defended interior. The 13th-century causeway was eventually demolished.

The medieval bridge beneath Chester Crown Court is similar to the bridge spanning the deep moat at Beeston Castle, the ruins of which can still be seen today.

Beeston Castle’s drawbridge was raised to prevent attackers from reaching the 13th-century gatehouse, and a similar arrangement may once have existed at Chester Castle, archaeologists have said.

Cheshire Constabulary PC Jonathan Lightfoot said: “I think it’s amazing that we can discover unknown archeology by doing proactive research and recording historic buildings.”

“This shows that we can now preserve this part of history so we can learn from it for future generations.”