well it is one of the looper moth caterpillars. but don't know which one. pick off or squish or systemic insecticide. personally I'd pick them off and feed them to the pond fish [they eat all sorts] or pop on the bird table.

Thanks Seaburn. Haven't got a pond, will put them on the bird table.

Aaar! poor little thing, live and let live it's only a few leaves!

they are usually laid in batches of 100-150! so they can totally strip a shrub. good food for birds so feed the birds :o)