Unknown Caterpillar

Unknown Caterpillar

Observation - Unknown Caterpillar - UK and Ireland. Description: Large caterpillar the longest I have seen about 3 crossing a coastal footpath over scrub land. I would have thought due to the size it may belong to a Hawk Moth?

Large caterpillar the longest I have seen about 3" crossing a coastal footpath over scrub land.
I would have thought due to the size it may belong to a Hawk Moth?