An unusual caterpillar

An unusual caterpillar

Observation - An unusual caterpillar. Description: This caterpillar was found under our picnic basket after spending a night camping by the River Cherwell in Oxfordshire. Does anyone know what it is? It was around 9-10cm long when fully stretched out.

This caterpillar was found under our picnic basket after spending a night camping by the River Cherwell in Oxfordshire. Does anyone know what it is? It was around 9-10cm long when fully stretched out.