Development viability appraisals should be provided on an "open book" basis where applicable. Any applicant who is not prepared to do this will nullify any rationale for lowering any S106 obligations. The presumption being that without verifiable evidence relating to site-specific economics, there is no justification for reducing S106 obligations. In such cases, the scheme will be considered viable and capable of meeting all planning obligations.

We stress that the LPA should publish the S106 agreement prior to granting planning permission, in line with the mandatory procedural requirement under Article 40(3)(b) of the Town and Country Planning (Development Management Procedure) (England) Order 2015 (DMPO). This allows the public to know the obligations secured, and to comment upon them if they wish, before planning permission is granted. The case of Greenfields (IOW) Limited v Isle of Wight Council [2025] EWCA Civ 488 is a helpful reference.