How a PPG17 Open Space Assessment Worked

A PPG17 open space assessment counted what a district already had, measured how far residents had to walk to reach it, and set a standard for what should be provided in future. The work rested on three things: a survey of every site, an audit of its quality and value, and a map of who could reach it. Planning policy then used those numbers to judge applications and to write local standards.

What a PPG17 open space assessment measured

Planning Policy Guidance 17, published by the UK government in 2002, asked local authorities to base open space policy on evidence rather than assertion. The assessment that followed had a fixed shape. Officers listed every open space in the district above a size threshold, usually 0.2 hectares, and recorded its type: parks and gardens, natural and semi-natural green space, amenity green space, provision for children and young people, allotments, cemeteries, civic spaces, and outdoor sports facilities. Each site got an address, a boundary, an owner, and a public or private status.

The audit then scored each site on two axes. Quality covered maintenance, drainage, litter, dog fouling, seating, paths, planting, and the condition of play equipment. Value covered how much the site mattered to the people who used it: its size, its accessibility, its range of facilities, and whether it served a particular group such as children or older residents. A large, well-kept park could score high on quality but low on value if few people lived near it. A small, scruffy kickabout could score the reverse. The two scores were kept apart on purpose, because a district needs to know whether to repair a site or to protect it.

Consultants ran this work for councils that lacked the staff to do it in house. Ashley Godfrey Associates, a planning and leisure practice at Ware in Hertfordshire, carried out open space studies of this kind between 2007 and 2019, including a PPG17 open space assessment for the London Borough of Harrow. The firm closed when its principal retired, and its service pages survive only in web archives, but the method they describe is the method councils still use.

How did the surveys and audits of local provision work?

The survey came first and it was physical. A fieldworker walked each site with a plan, a clipboard, and later a handheld GPS unit, and marked the boundary on an Ordnance Survey base. Photographs were taken from fixed points. Play equipment was itemised by type and age. Sports pitches were measured and their surfaces recorded. The result was a site-by-site record that could be checked by anyone who doubted a figure.

The audit came second and it was a judgement, so it needed rules. Quality and value were scored against a written matrix, usually on a scale of one to five, with a note explaining each score. Two assessors scoring the same site should reach the same number. Where they did not, the matrix was rewritten. This is the part that separates an assessment from an opinion: the criteria are published, so a developer or a residents' group can argue with the score rather than with the assessor.

Consultation ran alongside the field survey. Household surveys, school visits, and meetings with friends' groups asked what people used and what they lacked. The answers rarely matched the site data, and that gap was itself a finding. A district might have plenty of green space by area but none of it within a ten minute walk of the estates where demand was highest.

How was open space and its catchments mapped?

Mapping turned the site list into a picture of access. Each open space was drawn as a polygon on a geographic information system, with its type and its audit scores attached. Around each site the analyst drew a catchment: a straight line buffer, or better, a network distance measured along actual streets and footpaths. A park with a 400 metre walking catchment covers far less ground than a circle of the same radius, because walls, railways and rivers block the route.

Once the catchments were drawn, the analyst overlaid them on population data, usually output areas from the census. That produced a figure for each neighbourhood: how many residents lived within the catchment of a site of each type, and how many did not. Deprivation indices were added, because a gap in provision matters more where households have no car and no garden.

The maps also showed surplus. Some wards had three play areas within 300 metres of each other and none in the next ward. That pattern is common where provision grew piecemeal through planning obligations, each new housing scheme adding a small site on its own edge. Mapping made the imbalance visible in a way that a list of sites never did.

What did the assessment produce?

The final report set local standards. These were expressed in two ways: a quantity standard, such as 1.2 hectares of parks and gardens per 1,000 people, and an accessibility standard, such as a play area within 400 metres of every home. The standards were not national figures imposed from outside. They were derived from what the district already had, adjusted for what residents said they wanted, and tested against the catchments to see whether they were achievable.

The report also classified sites. Some were protected, some were surplus to requirements, and some were candidates for improvement. That classification fed directly into the local development framework. A planning application that would have removed a protected site could be refused on the evidence. An application in an area with a deficit could be required to provide a new site or a contribution towards one.

Why the method still matters

PPG17 was replaced in England by the National Planning Policy Framework in 2012, and the framework speaks of open space in broader terms. The underlying discipline did not change. A council still needs to know what it has, where it is, who can reach it, and what condition it is in before it can defend a decision at appeal. The assessments produced under PPG17 remain in use as the evidence base in many districts, sometimes a decade after they were written, because nothing has replaced them.

For a householder or a residents' group, the practical lesson is that the numbers are public. The site list, the audit scores, and the catchment maps sit in a council report that anyone can read. A claim that a neighbourhood is well served can be checked against the same figures the council used. That is the point of doing the work in the open.

What to look for in an old assessment

An assessment written under PPG17 will usually carry a date and a consultant's name. Check the date first, because catchments drawn before a large housing estate was built no longer describe the district. Check whether the audit scored quality and value separately, since a single combined score hides the difference between a site worth repairing and a site worth keeping. Check whether the catchments were measured along streets or drawn as circles, because circles overstate access. And check whether the standards were adopted in policy or merely noted in a report, since only the first carries weight in a planning decision.

A good assessment is dull to read. It is a list, a set of scores, and a map, with the reasoning written down so that someone else can follow it. That is what makes it useful years later, when the officer who wrote it has moved on and the only remaining witness is the document.