Privet Hawkmoth Caterpillar from the UK

Subject:  Weird big caterpillar
Geographic location of the bug:  North Norfolk UK
Date: 08/02/2018
Time: 03:05 PM EDT
Your letter to the bugman:  Hi,
Just found this bug eating our golden trumpet.
Every once in a while it shakes it’s head side to side.
Never seen anything like this in the UK before
How you want your letter signed:  Nick Bussey

Dear Nick,
This is a Hawkmoth Caterpillar in the family Sphingidae, commonly called a Hornworm, and we have identified it as a Privet Hawkmoth Caterpillar, Sphinx ligustri, thanks to an image on the Wildlife Insight site.  According to UK Moths:  “The large caterpillar is even more spectacular than the moth, being bright green with lilac and white stripes along the side, and a curved black ‘horn’ at the rear. It feeds on privet (Ligustrum), lilac (Syringa) and ash (Fraxinus).”  Neither site mentions golden trumpet as a food plant, but it is not unusual for a caterpillar to adapt to feeding from a different plant host if that plant is introduced as an ornamental plant within the range of the moth.

Hi Daniel,
Thank you for responding to my Email and identifying the caterpillar.
I was rather shocked to see something that large, generally caterpillars (and most other insects) are quite small in this part of the world.
The golden trumpet plants are quite new to the garden (around 10 days), they were purchased from an online plant centre so I suspect it may have already been attached when I took delivery.
I’ve now moved him (the caterpillar) from the garden and placed him on a tasty looking hedge at the front of the house where I hope he’ll be happy.
Thanks again for your information.
Best regards,
Nick.

Hi again Nick,
Relocating a Caterpillar to a plant it does not eat might mean it will starve.  Your individual looks quite mature, and perhaps it will survive by pupating.