A mighty web
When I saw these guy-roped webs enveloping large portions of gorse bush I assumed they were made by caterpillars, as is often the case. But I found none when I looked and concluded they were spider webs even though no spiders were visible. I didn't look hard enough for having established these webs are made by the gorse spider mite Tetranychus lintearius , I enlarged the photo and could make out hundreds of tiny red creatures clinging to the silk - see extra.
These mites are damaging to the plant and can inhibit its growth. For this reason they are used in Australia, New Zealand and other parts of the world where introduced gorse is invasive, as a biological control. to inhibit its spread.
Pembrokeshire is well endowed with gorse upon which the mites don't seem to make much impact and anyway we love its yellow blossom.