Interesting links:

Caterpillars

On a local walk at the weekend we noticed lots of these in the hedgerows.
Via the web I have had an identification from the
UK Moth man Ian who says they are the caterpillar of the Lackey Moth.
The caterpillars are far more colourful than the
moth. They live in the dense silk web that you can see in the top photo and it's thought to be a form of defence or shelter. They feed from April to June before hatching into moths in July/August.