Examines how the revision of PPG6 and subsequent refinement by a ministerial statement have caused confusion in planning applications for retail development. Describes the case of "Tesco Stores v SoS Environment" which questioned whether an extension to an existing store in a district centre required the applicant to demonstrate need. Tesco argued that the application site was within a district centre, an 'existing centre' as defined by the statement. The inspector interpreted 'existing centre' as only applicable to town centres and claimed that Tesco had to satisfy the need test. Tesco challenged this decision under the Town and Country Planning Act 1990 s288, on the grounds that the inspector had failed to correctly interpret government guidance on retail policy and did not determine whether the store was within a district centre. Tesco's challenge was allowed due to the ambiguity between PPG6 and the statement.