[First career as environmental economist] Because it would be astounding if we couldn't get a much better result for bats with a lot less money. e.g. You could buy 1,000 acres and let it go wild for £10m!

Or if you fancy saving wildlife in Namibia, you could buy 1,000 square kilometres for £8m.

yup! Exactly. Even for the stated aim of saving bats, the £100 million is being badly spent there

if everything is fungible why not build the whole railway in Namibia?

I'm not sure if you're serious, but the British government is trying to improve British infrastructure. A railway in Namibia wouldn't do that. If you're concerned about UK wildlife, you could do the 1000-acre rewilding Rob suggested much more cheaply than £100m and I bet it would many save more bats

the British government is trying to preserve British habitats. this isn't a matter of generic fungible "UK wildlife", it's a specific delicate ecosystem that has legal protection for a reason. even environmental economists understand this I thought

I can't tell you that you're wrong – if you value this particular habitat over others, then that's up to you. But I am sceptical that it is a good use of the money even from a bat-conservation point of view, and that there's a fair amount of "YIMBYs say it's good so I will say it's bad" going on

BTW this had led me down this delightful rabbit hole, which includes the discovery of Eurobats. jncc.gov.uk/our-work/ukb...