More than 120 people packed Oxford’s Southfield Golf Club to celebrate the designation of Warneford Meadow as a Town Green – and to fire a warning to a health trust.

Residents in Headington who formed the Friends of Warneford Meadow group mounted a long campaign to protect the 18-acre meadow next to Warneford Hospital from development.

But last month Oxfordshire County Council backed a planning inspector’s recommendation that the meadow – owned by Oxfordshire and Buckinghamshire Mental Health NHS Foundation Trust – should be granted Town Green status.

The decision followed a public inquiry last year into whether the site should be given the protected status.

Land can be registered as a Town Green if it has been used by local people for “lawful sports and pastimes” for 20 years.

But it is still not clear whether the health trust will appeal against the decision and campaigners are now urging the NHS to ditch the plan once and for all.

Trust spokesman Carrie-Ann Wade-Williams would only say: “We’re currently in discussion with our legal advisers, following our board meeting last week.”

The campaigners’ May Day meeting was addressed by Oxford environmentalist Mark Lynas and Prof Sir Muir Gray, the chief knowledge officer of the NHS.

Paul Deluce, the man who applied to register the meadow as a town green in December 2006, said: “This has been an amazingly successful campaign.

“I hope the NHS will accept that the council reached its decision after a very thorough public inquiry and won’t waste more time and public money fighting it in the courts.

“Instead it should talk to local people about how to protect the wildlife of this lovely meadow and enhance its value as an amenity for residents, hospital patients and staff.”

Campaigners gave evidence at the public inquiry in May last year to show local residents had used the meadow for recreation for at least 20 years.

They raised almost £40,000 to pay for the cost of being represented at the hearing.