Type of insurance for Scottish Nationalists? (5,5)

I believe the answer is:

third party

I'm a little stuck... Click here to teach me more about this clue!

'type of insurance' is the definition.
'third party' can be an answer for 'insurance' (I've seen this before). I am unsure of the 'type of' bit.

I can't explain the rest of the clue.

Can you help me to learn more?

(Other definitions for third party that I've seen before include "someone injured by driver?" , "Cover" , "Bystander perhaps" , "Liberals once?" , "Person not directly involved" .)

I've seen this clue in The Independent.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.