As the bounder is, the police just can't catch up with? (3,4,5)

I believe the answer is:

one jump ahead

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'as the bounder is the' is the definition.
I know nothing about this answer so I cannot judge whether it can be defined by this definition.

'police just can't catch up with?' is the wordplay.
I cannot quite understand how this works, but
'police' could be 'mp' (abbreviation for Military Police) and 'mp' is located in the answer.
'up' could be 'ahead' (similar in meaning) and 'ahead' is found within the answer.
This may be the basis of clue (or it may be nonsense).

Can you help me to learn more?

I've seen this clue in the Evening Standard.

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