Leaden cop messed up a means of controlling crime (5,4)

I believe the answer is:

penal code

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'up a means of controlling crime' is the definition.
I can't judge whether this defines the answer.

'leaden cop messed' is the wordplay.
'messed' indicates an anagram (letters get messed up).
'leaden'+'cop'='leadencop'
'leadencop' anagrammed gives 'PENAL CODE'.

Can you help me to learn more?

(Another definition for penal code that I've seen is " Legal principles".)

I've seen this clue in The Guardian.

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