• What are the most suitable mechanisms for assessing non-market valuations in this urban development context? • Who should be responsible for undertaking these valuations? If the private sector, how do public sector agencies assess its validity, and vice versa? • What scope is there for misuse? (i.e. either by supporting the case for development or, conversely, by justifying that a development shouldn’t proceed) • If viability is compromised by these valuations, does that mean development shouldn't go forward? What alternatives are there? • How does this form of valuation fit with policy and political priorities (e.g. if housing delivery is given priority over issues of planetary health) • How might central government and other agencies factor in these external costs in to their assessment mechanisms (e.g. UK Govt Green Book and RICS Red Book)?