Person to blame for a pasty mess (5)

I believe the answer is:

patsy

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

'person to blame' is the definition.
I can't judge whether this definition defines the answer.

'pasty mess' is the wordplay.
'mess' indicates anagramming the letters.
'pasty' with letters rearranged gives 'PATSY'.

'for a' is the link.

Can you help me to learn more?

(Other definitions for patsy that I've seen before include "Fall guy - girl's name" , "One who is taken advantage of (mainly US)" .)

I've seen this clue in the Evening Standard.

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