Crossword Genius

Furiously making kid suffer? (4-3-7)

Ross

I believe the answer is:

hell-for-leather

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

'furiously' is the definition.
I know nothing about this answer so I can't tell whether it can be defined by this definition.

'kid suffer?' is the wordplay.
I cannot quite see how this works, but
'kid' could be 'leather' (I've seen this before) and 'leather' is present in the answer.
This may be the basis of the clue (or it may be nonsense).

'making' is the link.

Can you help me to learn more?

I've seen this clue in The Independent.
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