Kate Ashbrook, who will speak at the Berkhamsted event

The country faces a new enclosure movement that threatens England’s public spaces, a campaigner warned.

Kate Ashbrook of the Open Spaces Society said insidious moves were afoot to deny walkers and outdoor enthusiasts access to green spaces.

The society’s general secretary spoke on the 150th anniversary of the famed ‘battle’ to free Berkhamsted Common.

On 6 March 1866, the year after its foundation, the Open Spaces Society organised a trainload of brawny navvies to pull down Lord Brownlow’s illegal iron fences and reopen the Hertfordshire common to the people. The OSS was acting on behalf of common-right-holder Augustus Smith.

In 1926 the common was acquired by the National Trust. This Sunday, the trust will join the Open Spaces Society to commemorate the event.

Ms Ashbrook said: “This was a great event in the society’s history, and showed the need for direct action to free the commons from unlawful enclosure and secure them as public assets.

“Today the society continues to campaign against enclosures. But the new enclosures are more insidious and just as serious.

Berkhamsted Common. Photo: Roger Jones CC-BY-SA-2.0

“We are fighting against unprecedented threats to our green spaces from all kinds of development. We must claim all the unrecorded historic public paths before the official map closes on 1 January 2026 when they will be lost for ever, disappear under concrete or be blocked off.

“Open spaces and paths were important in Victorian times, but they are even more vital today, for our health and wellbeing.

“The society is fighting the new enclosure movement with as much tenacity and energy as it fought the unlawful fencing of Berkhamsted Common 150 years ago.”

On Sunday afternoon the National Trust will lead a walk to show the location of the fencing followed by a barbecue. The trust’s ranger Emily Smith and Kate Ashbrook will speak.

Booking for the event is essential. Anyone interested should ring 01442 851227 or email the National Trust.