(1) Decisions on allowance for optimism bias are not policy matters for the PA. (2) The Information requested does not relate to site selection. (3) Site selections is not live policy and is unlikely to become so. (4) No safe space is needed. (5) There is a strong public interest in transparency in this case. (6) The Commissioner has not applied the public interest test to the information actually requested. The Appellant added that the Commissioner has also failed to take into account changing circumstances since 2020, including the cost increases and the many significant risks identified by the NAO. The Second Respondents response the Grounds of Appeal: 11. The reasons supporting the GoA were addressed in the public authority’s Response dated 24 July 2023 and are set out as follows; (1) “When a project of this nature is proposed, a business case is required. A business case is the repository for the evidence base in support of a spending proposal. Ministers consider the evidence presented to them in a business case when making decisions on policy. Within the business case for the HMLC project lie the ‘optimism bias’ figures referred to. Optimism bias is “the demonstrated systematic tendency for appraisers to be over-optimistic about key project parameters, including capital costs, operating costs, project duration and benefits delivery”. The aim of adjusting for optimism bias is to provide a more realistic assessment of the initial estimates of costs, benefits and time taken to implement a project. As the appraisal develops, more accurate costing of project or programme specific risk management can be undertaken, meaning adjustments for optimism bias may be reduced as more reliable estimates of specific risks are made. HM Treasury has issued supplementary guidance on the application of optimism bias and risk together with appropriate spending categories and values. In the instant matter, optimism bias has been used both to help estimate the likely costs of 5