Imagine you're about to move to a sizeable town or city anywhere in the UK. What would you expect to find in a good place to live? Good jobs and schools, obviously. You'd want to be able to get around easily so you'd look for an efficient public transport and road network. You'd expect all the local infrastructure to be in place: public services, healthcare, broadband, sports facilities, theatres and music venues.
You would also expect to find well maintained parks, relaxing open spaces and places where you can take children to play, go for a run or just sit in the sun. You would assume that a city which takes care of itself also takes care of its green spaces.
You might be surprised to find that most towns and cities have no obligation whatever to care for their green spaces. Local councils have no legal duty to preserve local ecosystems, keep parks and gardens open or preserve public access. No surprise then that green spaces are easy targets for spending cuts.
There is even fewer safeguards for green space that is in private hands. A study by the London Wildlife Trust in 2010 found that nearly a quarter of the capital's green spaces were private gardens - and while they are rich in wildlife and a vital ecological resource, more than one third of this garden space has already been paved or tarmacked over.
There is a better way, and it's one many of us can find on our doorsteps. The idea that publicly accessible green spaces are a shared benefit, to be enjoyed and cared for, is an ancient one. It is captured in the concept of the commons, areas of land on which local residents enjoyed particular rights and privileges.
The remaining historic commons in England and Wales are now covered by legislation, the Commons Act 2006, that protects public access and reaffirms the responsibilities of stewardship and maintenance. What is significant about the commons is not who owns the land - many are privately owned - but the continuing right of public enjoyment and duty of care. They provide a model for flexible partnerships of public, private and voluntary interests working for everyone's good.
A report published this week to mark the 30th anniversary of the community and environmental charity Groundwork argues that this model of the commons should be applied to all publicly accessible parks and green spaces, enshrining in perpetuity their role and value as public goods, as well as the responsibilities of care that accompany public rights and privileges.
Wanstead Flats in east London, on the border between Newham and Redbridge, is typical of Britain's commons. On a Saturday you might find football teams playing in organised amateur leagues; kids learning to ride bikes or feeding ducks on the pond; dog walkers, runners, cyclists and model aircraft enthusiasts. In the past you might even find someone exercising their traditional right to graze cattle.
There are more than 7,000 commons in England, covering nearly 400,000 hectares - 3% of the country's land. Contrary to popular folklore, they are not everybody's property. Many are privately owned: Wanstead Flats, for example, is part of Epping Forest, owned by the City of London Corporation.
Despite names that often suggest poor quality land of low value - Wormwood Scrubs, Roadside Waste, Nether Mire - these commons are hugely important. Nearly half England's common land lies within national parks, 30% within areas of outstanding natural beauty, and one fifth of them are within sites of special scientific interest. More than one tenth of England's scheduled ancient monuments are on common land.
The commons are vestiges of much larger areas that were historically open to all for foraging, grazing and recreation. Although these open spaces are no longer required for subsistence, they are recognised as public goods that provide benefits to all of us.
Far from being a historical anomaly, the commons have been a rallying point for civic pride and involvement and are seen as prized local assets. They have also been centres of protest and politics: Blackheath was the setting for Wat Tyler's Peasants' Revolt of 1381, while Putney Heath hosted the famous Putney Debates during the English Civil War in 1647.
This belief that green and open spaces are a public good, whether or not they are communally or state-owned, has been reinforced when put to the test by government. When the government proposed the sale of Forestry Commission land in 2010, a petition of protest attracted more than 530,000 signatures. Polls suggested 84% of the country opposed the sale, and in February 2011 the plans were unceremoniously ditched.
The Independent Panel on Forestry, chaired by Bishop of Liverpool James Jones, published its interim report in December 2011. More than 42,000 people responded to the panel's call for views. Bishop Jones reported, tellingly: "They overwhelmingly expressed their passion for the public forest estate, and woods more generally, as places of recreation, a way to connect with nature and as a vital source of resources."
The concept of the commons puts this idea of a public good on clear legal foundations. What's more, it makes it clear that access and stewardship are the twin pillars that create the public good: ownership is secondary.
So imagine the thinking behind Groundwork's report is put into practice. Instead of relying on lobbying, largesse or luck, every town or city would have a clear responsibility to look after its green spaces. All owners would have a duty of stewardship, requiring them to understand the environmental and social value of the places under their care, and to look after them in ways that maintain and enhance that value.
Each locality would decide which approach best fulfilled its duties and met its needs. In some places independent, directly elected parks boards would invest in green spaces through local taxation, like the Parks and Recreation Board in Minneapolis. In others, local councils would take responsibility in order to better integrate local green infrastructure with the planning system. Some might delegate management to community-owned charitable trusts, paying them an agreed fee for their services. All could raise revenue by contracting with healthcare organisations to provide a 'natural health service' to reduce the incidence of obesity and cardiovascular disease.
We have a model for shared responsibilities and public access that could preserve and improve our green spaces for generations to come. We have legislation that could be easily adapted. All we lack is the will to safeguard what we all value.