Where was it found? It's helpful to know the food plant.perhaps it was off to pupate somewhere. Couldn't spot anything quite identical in my book.

In my book, it does look like the caterpillar of the Black veined white....bit of a pest Amsterdam. Do you have apple trees? The female lays it's eggs on the underside of fruit tree leaves, mainly apple.

Just checked online Amsterdam, and it is extinct in the UK, but it does look like it..

Cat brought it in and yes I have apple trees! I released it back into the garden thinking I was doing my bit for nature! I certainly have not seen anything like this one before......

Well, you could be bringing the species back here....google it and have a look. Won't be too good for your apple, or fruit trees in Shropshire though....:((

I’m nit too sure so sent it off for an id from brutush butterfly/moth experts. Will let you know when I get an answer.

Please do. I now think it could be the larva of The Duke of Burgandy Frittillary. A Black veined white would be quite a find.

According to Steve from Wildlife insight it’s a buff tip moth caterpillar.

Ok...going to have to check them now....you've started something now Amsterdam...ha ha!

Mmmm......

Thank you for the update, Amsterdam.