LONDON — The Port of London Authority implemented new mudlarking permit regulations in 2024, designating four categories of permits and initially announcing that most existing license holders would lose their authorization. Following public outcry, the authority reversed course and established renewal criteria for current permittees.

Mudlarking—the practice of searching for lost and ancient objects along the Thames riverbanks—has evolved from an unregulated pastime into a tightly controlled activity. The Port of London Authority, which owns the vast majority of the Thames riverbed within London, now prohibits searching the foreshore without a permit, though casual strolling remains allowed. Until approximately ten years ago, anyone could freely search the river’s edge without official permission.

The regulatory shift began in late 2016, when the Port of London Authority first announced that permits would be required to search and scrape the Thames shore. Between 2019 and 2022, the number of licensed mudlarks in London surged to five thousand, prompting the authority to stop issuing new permits and open a waiting list. That list was later closed once it reached ten thousand names. Currently, individuals are unable to join a waiting list for mudlarking permits.

Since 2024, the authority has structured access through four distinct permit categories. Among them are fifty “creative” permits that allow holders to produce and sell jewelry and artworks made from their finds—unlike standard permittees, who are generally allowed to keep what they discover but must not sell it. The foreshore’s anaerobic mud is known to preserve artifacts for centuries, making the Thames a rich repository of historical objects.

In early 2024, the Port of London Authority announced that most existing mudlarks would lose their licenses and be placed at the back of the waiting list. The move triggered significant backlash from the mudlarking community. In response, the authority permitted some current license holders to renew their permits under new criteria.

These include at least four years of mudlarking experience, a documented history of reporting finds to the Portable Antiquities Scheme—an archaeological service run by the British Museum—and contributions to the educational, cultural, and historic life of London. The four-year experience requirement may be waived in certain cases. Approximately half of all renewal applications are approved.

James Trimmer, director of planning and development at the Port of London Authority, defended the regulatory changes. “Hobbies ended up being codified, because more people started doing it. And without wishing to portray myself as some sort of Victorian gentleman this couldn’t keep carrying on as it was,” he said. Trimmer, a surveyor by training who has worked at the authority for twenty-seven years, oversees the implementation of these policies.

Despite the restrictions, discoveries continue. In the summer of 2024, mudlarker Bolly May found a large gold Tudor ring featuring a pale amethyst embedded in the Thames mud. “Two more tides, and that would have washed away,” May said, highlighting the fleeting nature of such finds.

Other mudlarks have echoed the emotional and historical resonance of the activity. Jessica Forde, a mudlark, emphasized storytelling over monetary value: “When people say to me, ‘What’s the most valuable thing on your table?,’ I cringe. I’ve got no idea. I’m not interested. What’s relevant is the stories about how these things were made, who made them, where they came from.”

The Port of London is the U.K.’s busiest port by tonnage, and its riverbed is a legally protected archaeological resource. The rise in mudlarking’s popularity—from its origins in the late 18th century as a survival activity for impoverished children collecting coal and rope, to today’s hobbyist pursuit—has strained the balance between public access and heritage preservation. The Society of Thames Mudlarks has held a unique city license since the 1970s allowing digs up to four feet, three and one-eighth inches deep, but general access has tightened significantly.

The 2024 policy shift reflects a broader effort to manage cultural heritage amid growing public interest. By instituting renewal criteria and capping access, the Port of London Authority aims to ensure that mudlarking remains sustainable and contributes meaningfully to London’s historical record. Health concerns, such as exposure to Weil’s disease spread by rat urine in the tidal mud, also underpin safety protocols associated with permits.