The City of London Corporation (CLC) said commercial foragers had been targeting the forest which poses a threat to biodiversity.

It said the removal of mushrooms deprived animals such as deer of a food source.

Ancient trees also rely on fungus to protect their roots, it added.

The corporation, which owns and manages the forest, is warning the fungus pickers that they could be fined or prosecuted for gathering mushrooms, which are protected under Epping Forest byelaws.

Confisgated fungi

Confisgated fungi

In a recent incident, one person was caught with a 49kg haul, the equivalent to multiple large black sacks.

The City Corporation has been clamping down on fungi foraging over recent years, issuing fines and prosecuting 27 people since 2014.

Graeme Doshi-Smith, Chairman of the City of London Corporation’s Epping Forest and Commons Committee, said: “We are urging people not to pick mushrooms in any quantity.

“Their irresponsible actions are damaging the green lungs of London and spoiling the enjoyment of visitors.

Confisgated fungi

Confisgated fungi

“Our job is to protect the future of this ancient woodland which is of national and international conservation importance.

“We will not tolerate criminal activity in Epping Forest and we will take swift action against anyone damaging wildlife and threatening rare species.”

According to the CLC, Epping Forest, has more than a million trees, including ancient pollards of beech, hornbeam and oak, and is home to around 500 rare and endangered insect species.