Whether or not there is a legal duty to consult, where consultation is carried out it must be done fairly. What is fair will depend on the circumstances of the case and the nature of the proposals under consideration (R (Edwards) v Environment Agency  EWCA Civ 877).
Subject to the overall requirements of fairness, the decision-maker will have a broad discretion as to how consultation should be carried out (R (Greenpeace) v Secretary of State for Trade and Industry  EWHC 311), and what should be consulted upon (R (The Vale of Glamorgan) v The Lord Chancellor and Secretary of State for Justice  EWHC 1532).
The consultation must also comply with the following principles (termed the Gunning principles after the case in which they were set out, or the Sedley requirements after the barrister that suggested them in that case) (Initially set out in R v Brent London Borough Council, ex parte Gunning  84 LGR 168).
- Consultation must take place when the proposal is at a formative stage. Public authorities must have an open mind during consultation and must not have already made the decision, but may have some ideas about the proposal.
- Sufficient reasons must be put forward for the proposal so as to allow for intelligent consideration and response. Consultees must have enough information to be able to make an informed input to the process.
- Adequate time must be given for consideration and response. The timing and environment of the consultation must be appropriate, sufficient time must be given for people to develop an informed opinion and then provide feedback, and sufficient time must be given for the results to be analysed.
- The product of the consultation must be conscientiously taken into account.
It is prudent for a decision-maker to show in its decision that it has undertaken consultation and has given proper weight to the representations received. This may involve the decision-maker showing that it has understood the points being made by the responses and has considered them.