Top man in Hatton Garden included in deal? (4,2,8)

I believe the answer is:

king of diamonds

'included in deal?' is the definition.
(the playing card might be dealt out)

'top man in hatton garden' is the wordplay.
I cannot really see how this works, but
'man' could be 'king' (king is a kind of man) and 'king' is found within the answer.
This may be the basis of clue (or it may be nonsense).

I've seen this clue in The Guardian.

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