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The power of evidence in the planning system

11 June 2018 Author: Yvonne Rydin

Much of planners’ time is spent collecting evidence for plan-making and considering evidence that has been submitted in regulatory contexts. But planning is about considering the future – the future trajectory of an area, the future impacts of a development – and this inevitably brings uncertainty in. How does the planning system handle evidence in situations of uncertainty?

Recent research by a team at UCL has looked into the operation of the 2008 Planning Act for Nationally Significant Infrastructure Projects, examining in particular 12 major renewable energy projects that had been through the process.

Using a mass of data from the Examination Authorities’ reports, focus groups, supplementary documents, a survey and some non-participant observation, the team was able to trace how knowledge claims – presented as evidence – impacted on the process and people’s experiences of that process.

Evidence-based planning: what does it mean for local communities

It was clear that for evidence to carry weight it needs to be technically framed and supported by guidance or best practice documentation or the personal expertise of the organisation presenting the evidence.

This does not mean that the knowledge of local actors – residents, wildlife NGOs etc – cannot contribute (there are cases of local groups providing evidence or prompting evidence to be collected or revised), but it has to be presented in terms equivalent to that from the local authority or expert agencies, such as Natural England. This may cause problems for some local communities who lack the skills, time and other resources to do so.

The regulatory process provides a space for evidence to be contested; it was the ambition that this new regulatory regime would adopt an interrogatory rather than adversarial approach and this does seem to be happening.

Mechanisms to close down debate on evidence

However, the process is also tightly time-constrained; the examination phase can only last six months at the most. So there is frequent recourse to measures to close down ‘too much’ debate and turn contested and uncertain knowledge into “firm enough” evidence for a regulatory decision.

There are three mechanisms at work that enable this closing down of debate.

First, there is recourse to the views of expert agencies such as Natural England and the Environment Agency, who are held to have specialist knowledge on key areas of debate, such as the impact of wind farms on bird populations or of noise pollution on fish breeding grounds.

Second, there is the use of a Statement of Common Ground to record agreement between parties on a range of issues (impact assessment methodologies, scale and nature of impacts). In doing so, the Statement effectively take those issues off the table.

Third, the experience of the regulators themselves – the Examining Authorities – can be important, as when they are able to view the environmental context of proposed projects themselves and judge the evidence on potential landscape and seascape impacts. The site visits, both accompanied and unaccompanied, can play a vital role here.

Communities need support to use evidence to their advantage

These findings suggest certain institutional changes are needed to support local communities when they seek to get involved in the regulatory process. For the team’s research also found that local communities often expressed deep unhappiness with the current process and over their ability to have any influence. It may be necessary to find a way to help local community groups gain access to information and expertise and frame their evidence in appropriate ways.

Similarly local actors – residents, fishermen, wildlife groups – may need support in participating in the examination process, which they often find extremely daunting. It has been suggested that a ‘Mckenzie Friend’ – to adopt a legal parallel – may be appropriate. A log of Statements of Common Ground that have been agreed could be a useful way of drawing attention to the importance of this mechanism.

And, finally, the existing best practice among Examining Authorities in enabling local people to feel comfortable with the process should be more widely disseminated within the Planning Inspectorate.

The full paper is available on Open Access and the UCL team can be contacted through Yvonne Rydin at

Guest blogs may not represent the views of the RTPI.

Yvonne Rydin

Yvonne Rydin

Yvonne Rydin is Professor of Planning, Environment and Public Policy at the Bartlett School of Planning, University College London.