The site of the former Sacred Heart School and the playing field in Mersey Road, Redcar, have become overgrown and closed to the public.
Ian Swales Liberal Democrats Prospective Parliamentary Candidate for Redcar said: "As a condition of the planning permission for the new Sacred Heart School it was agreed that the former site would be retained as public open space to compensate for the loss of green space on the new site.
"It is now more than two years since the new school opened and the old school has been demolished."
Lib Dem campaigner John Hannon and a former Sacred Heart pupil, has called on the Council to honour its agreement to open the land up to the public. "The grass has not been cut for months and the land has become over overgrown and neglected."