Deeds of Dedication provide statutory protection for green space for future generations.
Whilst this is carried out by your local authority (council)’s legal team, a friends group can get advise and the appropriate form from the charity Fields In Trust. They can then fill this in, supply the OS map and photos required, and ask their Ward councilllors or park worker to hand the form in for their portfolio holder to finish the process.
Some London borough councils have led the way in this movement and registered all their open spaces.