Eighty-year-old Dennis has devoted his life to returning eagles, osprey, red kites and red squirrels to Britain. But, he says, there is still plenty to do. And he is thrilled by the can-do attitude he gets from young people today

As he strolls beside Loch Garten in his fleece, binoculars around his neck, Roy Dennis looks every inch the spry, bird-loving grandad that he is. With his soft Hampshire burr and genial demeanour, it seems like he wouldn’t say boo to a goose. First impressions are deceptive, however. Dennis is the most significant conservationist you’ve probably never heard of, and possessed of a radicalism that would startle the most outspoken young environmentalist.

The first hint emerges when Dennis, who is 80 and still climbs trees, remarks that no one over 60 should vote. He explains that older people are making decisions over the climate crisis and wildlife loss that they won’t be around to be accountable for; he recently decided voting should start at 12, the age of his youngest child, Phoebe, but she told him it should be 14. It is easy to say radical things, but Dennis’s vision of how to halt the extinction crisis and restore lost habitats and species in Britain deserves attention because it is rooted in 60 years of pioneering conservation action.