In South East UK we found this hairy caterpillar with a brown hairy body, red dots forming a line on it's back, four yellow knobs on it's back and two long antennae and suckers on its feet . We've searched but can't find it anywhere to identify. Please could someone help to identify it.
it was crawling up the window and I think it might have hatched from a piece of cobweb that I saw on the window.
The Vapourer moth (Orgyia antiqua), it would have hatched from an egg some time ago. I suppose the cobweb could have been its cocoon that it had abandoned, they do look quite cobweb-like, but it doesn't look like it is a pre-pupatory caterpillar that has abandoned its cocoon.
As a child I was fascinated by cocoons I would find beneath the window sills of my house that were covered in eggs, often with the remains of the chrysalis still poking out. I brought one of these cocoons into the house and was surprised at the large grey wingless moth that hatched out. within a few hours we must have had 20 small reddish brown male vapourer moths hanging from our net curtains attracted by her pheremone trail, all trying to mate with the awaiting female. When she was mated I was astonished to watch her lay her eggs on her old cocoon with seemingly mathematical precision.