BEIS has not spelt out the assumptions underpinning its ambitions to decarbonise the public sector, in particular the extent to which it is relying on technological innovation to meet its long-term targets. BEIS told us that it expects electric heat pumps to fall to around the same price as gas boilers by 2030 and that hydrogen may also play a role in decarbonising the public estate, although the relevant technology is not yet mature.12 Although its impact will be broader than public sector decarbonisation, BEIS stated that it expects to have four functioning carbon capture and storage clusters in place by 2030.13 We accept that predicting future costs and developments in technology is challenging and uncertain, which is why it is important for government to be clear about any assumptions it makes in this area.14 Setting standards for measurement and reporting