Far out in the Channel, the lights of ships at anchor flickered while the lighthouse at Anvil Point emitted its steadier beam. Late on, a crescent moon shone a coppery orange.
But, undoubtedly, the most extraordinary light source to be seen was the vivid green gleam from the glow-worms that inhabit the herb-rich grassland on the cliffs and quarries in this tucked-away corner of southern Britain.
“It is a wonderful sight,” said Ben Cooke, the National Trust area ranger for Purbeck in Dorset, whose job includes monitoring the glow-worms and caring for their habitat.
“Seeing glow-worms should be on everyone’s bucket list. There’s nothing else like it in this country. The first time you see one, it’s such a ‘wow’ moment.
“If you start out early enough and the light gradually fades, it plays tricks on your eyes. People see a white flower and think: ‘Oh, is that one?’ Or raindrops on a leaf catch a bit of light. But when you actually see the glow, you can’t mistake if for anything else. It’s like an LED light, really piercing.”
The National Trust is running a project in Purbeck involving volunteer spotters counting the numbers of glow-worms. It is working on providing the ideal conditions for them to thrive and may look at introducing more into the area.
Cooke took the Guardian on a glow-worm walk this week. Close to Seacombe Cliff, two females were glowing brightly to attract passing males. A little further along the path, Cooke set up a “trap” – a bike light under a plastic bowl – to attract other males. Within a few minutes 14 had appeared. “A record for me,” he said. The males, which fly as they search for females, do not emit the same bright green light.
Many writers have waxed lyrical about glow-worms, not least the Dorset writer Thomas Hardy, who wrote a scene in his novel The Return of the Native in which two characters played a game of dice using the light from 13 glowworms.