Green caterpillar

Green caterpillar

Observation - Green caterpillar. Description: Large green caterpillar (2-2 half inches) found on a slab at the allotment, before it disappeard down under the shed. Can anyone i.d it please, I have never seen any caterpillar as large as this before.

Large green caterpillar (2-2 half inches) found on a slab at the allotment, before it disappeard down under the shed. Can anyone i.d it please, I have never seen any caterpillar as large as this before.