“There are the most extraordinary things we could learn from them,” says Brian Briggs, as he checks yet another of the bat boxes that he and his wife, Patty, have put up just outside Heathrow. “They’re completely fascinating, from all kinds of angles.”

It’s a damp Sunday morning at Bedfont Lakes country park, and the Nathusius’ research project team, led by Patty, is checking the artificial roosters, looking at the health and number of different bat species. This outing, however, is a little different from normal; the conversation is focused not on the bats but on the government’s planning and infrastructure bill, which the following day will be having its final reading in the House of Lords.

The group believes the bill will undo decades of progress in the conservation of protected species. “They’re going to derail all the good conservation work that this country has been notable for,” says Patty, while noting down the bats she has found in the roosting boxes. “We need to look after what’s left.”