The screening exercise and mitigation measures – once more

The court in R (on the application of Devon Wildlife Trust) v Teignbridge District Council (see PP 2015/152) also considered the extent to which a local planning authority is entitled to have regard to proposed mitigation measures, when adopting a screening opinion for the purposes of the Town and Country Planning (Environmental Impact Assessment) Regulations 2011 (“the EIA Regulations”). This is an issue that must always be addressed in the light of an overriding principle previously accepted by the courts, namely that reliance cannot be placed upon mitigation measures at the stage of granting planning permission to dispense retrospectively with the requirement for an environmental impact assessment that should have been initiated at the outset. In Devon Wildlife Trust, Hickinbottom J drew the following four propositions from earlier decisions: (1) In considering whether a project would be likely to have significant effects on the environment, the relevant authority has to exercise its planning judgment, taking into account all material factors. (2) In making that practical judgment, the authority is not as a matter of law required to ignore proposals for remedial or mitigation measures; indeed, relevant remedial or mitigation measures may be a material factor which it is required to take into account. (3) The authority must decide whether, on the information available to it, the proposal (including any remedial or mitigation measures) is likely to have significant effects on the environment, having regard to the precautionary principle and to the degree of uncertainty with regard to the measures at the date of the decision. In some cases, there will be such uncertainties that the proper implementation of the measures cannot be assumed. However, in other cases, the effectiveness of conditions or proposed remedial or ameliorative measures will not be crucial to the opinion; or, alternatively, at the time of consideration that effectiveness can be predicted with confidence. In those cases, the authority may properly decide that, looking at the project as a whole (including such measures), there is no serious possibility of significant effect on the environment. (4)Whether the authority has sufficient information to make a decision that there will likely be no significant effects on the environment – and, if it has such information, the screening decision itself – are matters of planning judgment, in respect of which the authority has a wide discretion. In practical terms, this stresses the importance for a developer to include within the project at the outset all appropriate mitigating features. John Martin is a planning law consultant