large caterpillar

Observation - large caterpillar - UK and Ireland. Description: Can anyone help with identifying a caterpillar, (presumably a moth, because I know butterfly ones better). over 2 inches, nearly 3. about a dozen of them eating through alder or willow leaves on edge of field in Devon. light green, hairy, yellow and blac

Can anyone help with identifying a caterpillar, (presumably a moth, because I know butterfly ones better). over 2 inches, nearly 3. about a dozen of them eating through alder or willow leaves on edge of field in Devon. light green, hairy, yellow and black markings in disrupted rings all the way along its length. sorry no photo.