the HMLC project and also to inform the economic case, which assesses costs and benefits as part of an overall assessment of value for money. The information requested forms part of the HMLC business case and is therefore exempt from disclosure under s.35(1)(a) of FOIA as it relates to the formulation and development of government policy; specifically, the means by which government will fulfil its commitment (that DLUHC leads on delivering) to establish the HMLC. The policy is one of “government policy” as the final policy decisions relating to the delivery of the HMLC are subject to approval by the Department’s Ministers. The Business Case relates to the HMLC being designed and built in the Victoria Tower Gardens (“VTG”). Although the Government’s commitment to building a HMLC was announced in January 2015, the policy on delivering the various components of this project is still under development. Policy decisions on the operation of HMLC will continue to be taken up until the point that it is built and functioning. Decisions relating in particular to the delivery and site selection of the HMLC will continue to be live policy until all necessary consents for the selected site have been awarded and construction is underway. The purpose of using optimism bias and putting a business case together is to inform policy decisions. The Appellant clearly has a mistaken view that optimism bias is approached in a mechanistic manner with reference to numbers only, by taking figures from Treasury Guidance, applying them to the project, and that it is simply a matter of providing those figures from the business case to the Appellant. When in fact, a lot of carefully considered and debated judgement is required at each stage of the decision-making process in order to formulate the business case, and in order to inform the wider decisionmaking process about the design and build of the HMLC. The application of HMT’s guidance on optimism bias to the estimates of construction costs require judgements to be made in relation to the degree of risk associated with construction of a particular design on a particular site. When applied to the economic case, the application of optimism bias estimates requires judgements to be made in relation to a wide range of factors including the degree of confidence in responses to opinion surveys. Those considerations are not capable of mechanistic extraction without providing very large sections or even the whole of the business case to give context to the figures. In order to answer the Appellant’s FOIA request, therefore, figures alone cannot be provided as they will not make sense. The whole business case, or very large parts of it, would need to be given. In doing so, this would expose a 6