Planning analysis: The conclusive provisions of section 56(1) of the Wildlife and Countryside Act 1981 (WCA 1981) do not apply when reviewing a definitive map and statement to decide whether a modification order should be made. Instead, there is an evidential presumption against changing the definitive map. This can be rebutted if there is ‘evidence of some substance’ to show, on the balance of probabilities, that a modification should be made. The evidential presumption applies to the most recent version of the definitive map and statement. However, where the review process reveals that the most recent version is in error, the presumption applies to the previous version. In this case the error in the definitive map had been present from the first version. Therefore, the presumption was of no assistance and the decision whether to modify the map had to be made on the balance of probabilities, having regard to all of the available evidence. Written by Emma Dring, barrister at Cornerstone Barristers.