A bone fragment has been uncovered during a routine drainage sweep at Shepton Mallet Prison, prompting an investigation into its origin.

Staff at the historic site, formerly the UK's longest-operating prison until its closure, discovered the small bone deep within a drain in a staff-only section of the exercise yard. The item was found alongside contraband such as makeshift weapons, drug paraphernalia, sharpened toothbrushes, bullet casings and lighters—typical remnants of the prison's operational past.

Cove Attractions, which now manages the site as a heritage attraction, carried out the sweep as part of ongoing safety checks. Although the prison has undergone extensive searches since being repurposed, some areas remain restricted to staff and continue to yield historical artefacts.

The drainage area where the bone was located sits above the site of the prison's original subterranean cells, which date back centuries. The operators have now launched a formal investigation to determine whether the bone is of human or animal origin.

A spokesperson for Cove Attractions said: "We fully expect the bone to be animal, but with the incredible depth of history here, we have a duty to be thorough. This isn't just any building. It's the oldest prison in the UK, and every brick, corridor and drain could hold a story."

The site, which opened in 1610, has previously served as a military detention centre and was the location of multiple executions. It remains open to the public, offering guided tours and heritage experiences.

Cove Attractions confirmed they are working with the relevant authorities and expect results from the investigation in due course.