Heathrow Connection: combining evaluation and consultation for the Heathrow Airport Expansion Consultation

  • Client

    Heathrow Community Engagement Board Ltd. (HCEB)

  • Sectors


  • Services



We were recently asked to evaluate the delivery of the Heathrow Airport Expansion Consultation by the Heathrow Community Engagement Board Ltd. (HCEB). This gave us a very exciting opportunity to combine two of our areas of expertise: consultation and evaluation. We have a long history of delivering engagement and consultation activity, and have a detailed understanding of the requirements, so it only made sense that we make use of this and bring these skills together with our established expertise in evaluation.  At Traverse we pride ourselves on the multi-skilled nature of our people, so this kind of cross-service working gives us a great chance to flex some different thinking muscles!

What HCEB had to say about working with Traverse:

 “We really enjoyed working with Traverse and the expertise offered by the team has helped HCEB successfully deliver a key objective. We have been impressed with the breadth of specialist thinking and skills that Traverse provides and we have learned a great deal ourselves about the what good consultation practice should look like.”

Heathrow Community Engagement Board Ltd. (HCEB)


Our Approach

We used a ‘process evaluation’ approach, which sought to establish whether and the extent to which Heathrow Airport Limited delivered the Airport Expansion Consultation in line with best practice. This exercise sought to:

  • Draw evidence-based conclusions in relation to whether, and the extent to which a project or programme, achieved its stated objectives;
  • Capture the learning generated during a project or programme for the purposes of improvement;
  • Understand and, where possible, measure the nature and extent of change that has taken place as a result of a project or programme; and
  • Generate clear and actionable findings to support current and future work.

We carried out a desk-based review of existing legislation, case law, guidance and best practice. The findings of this review formed the basis of the principles which constitute the outcomes for this evaluation. Heathrow’s adherence to these principles was then assessed based on a further review of consultation documentation (including the consultation materials and information, feedback form, PEIR, PTIR, planning and proposal documents, code of construction practice and Equality Impact Assessment), additional research (commissioned by HCEB from YouGov, Britainthinks, Collingwood and Temple) and views expressed by local authorities in their published responses to the consultation.

We agreed four questions with HCEB that formed the basis of the evaluation:




What is best practice for consultation relating to an NSIP?

Adherence to standards

To what extent did the Heathrow Airport Expansion Consultation adhere to best practice principles?

Alternative models

Are there any elements of the engagement process undertaken by Vienna Airport that Heathrow might follow in the future?

Conclusions and recommendations

How could Heathrow improve its consultation practice in future?

There is a growing body of case law around consultation, but this ever-developing picture is based on five widely accepted principles (for more information about the legal background of consultation, you might also like to see our blog on the principles of consultation). The Heathrow proposals are considered a ‘Nationally Significant Infrastructure Project’ and the consultation was a statutory consultation in support of an application for development consent. As such there were also particular legal requirements that the consultation needed to meet. These were also taken into consideration in assessing the consultation.

These principles and the regulatory requirements formed the basis of our evaluation framework:


Success indicators

Principle 1 – Consultees should be able to shape the proposals.

This principle establishes a requirement that there should be scope to amend or change proposals being consulted on. It should be clear that there is capacity to adjust or amend the proposals and that the promoter remains genuinely open to change and that the consultation is being undertaken at an appropriate point in the project where changes to proposals are possible. 

It is clear how the outcomes of the consultation have fed or will feed into any decision-making process.

Consultation takes place in stages, with more information available during latter stages.

Information about alternatives either considered at a previous stage or open for consideration is freely and accessibly available in both technical and non-technical form.

Principle 2 – Enough information should be provided to inform consultees’ views.

The information provided for a consultation should be sufficiently detailed for all consultees to understand the proposals, the rationale which underpins them, and the key factors underpinning the decision-making process.

Information is provided which is sufficiently detailed for a reasonable person to make a judgement on the proposals.

Principle 3 – Information should be provided in a format which is clear and easy to understand.

Information provided should be as easy as possible to understand for anyone who wishes to respond to the consultation, whilst still providing consultees with sufficient information in line with Principle 2. The provision of information should recognise the differing level of technical understanding amongst the stakeholders and the public. Best practice would therefore be to include information in a range of formats and in an engaging and accessible way that caters for any and all audiences.

Information should be easy to understand.

Information should be presented in an engaging way.

Documents should use plain English, minimise acronym use and be as short as possible (whilst adhering to Principle 2).

Questionnaires should minimise the number of questions to which consultees must respond.

Questions should be as clear as possible.

Principle 4 – The methods and channels used to consult should be appropriate for all relevant audiences.

The form of consultation should consider the characteristics and related needs of those potentially affected by any decision or would be likely to respond to the consultation and their ability to access information and respond to the consultation. This includes considerations such as language and reading ability, routes to obtain information and ability to provide a response.

A range of response channels should be available.

Consideration should be given to the needs of any relevant audience to the consultation.

Principle 5 – The consultation should last an appropriate amount of time.

The Planning Act 2008, which sets out the legislative requirements for statutory consultation in relation to DCO applications, establishes a minimum period of 28 days for consultation. However, the length of time that a consultation should remain open should consider the nature and complexity of the proposals, the way in which the consultation is being delivered and the characteristics of the consultees. Consideration should also be given to the time required to notify consultees about the consultation, and the time they would need to access and understand information and develop their response.

The consultation must last a minimum of 28 days but should last for a period which takes into account:

  • The complexity of the proposals
  • The response channels adopted for the consultation
  • The characteristics of the consultees
  • Any other factor which might impinge on the ability of a consultee to respond promptly, such as holidays or election periods

International Comparisons

We were also asked to assess any learning that could be gained from other engagement models used elsewhere in the world. Vienna Airport’s approach, which uses a ‘Dialogue Forum’, was identified as an acknowledged exemplar of good practice and a comparable context that used a different model. We were able to examine the regulatory and functional frameworks within which each Airport was operating and from there identify elements of Vienna Airport’s approach that might be transferable to Heathrow.



We were able to provide a detailed examination of the consultation that had been delivered, identifying lessons which might be applied to future consultations and learning from the Vienna Airport engagement model. Our report informed HCEB’s response to the consultation, which you can find here.

We valued and enjoyed this chance to apply our knowledge in a different way and contribute to enhancing consultation on this important project.


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Other Key Staff:

Who We Work With

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