Most robust force used in breaking the ties (8)

I believe the answer is:

heftiest

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'most robust' is the definition.
(robust can mean hefty or strong)

'force used in breaking the ties' is the wordplay.
'force' becomes 'heft' (I can't explain this - if you can you should give a lot more credence to this answer).
'used in' is an insertion indicator.
'breaking' indicates an anagram (back).
'ties' anagrammed gives 'iest'.
'heft' inserted into 'iest' is 'HEFTIEST'.

Can you help me to learn more?

(Another definition for heftiest that I've seen is " Brawniest".)

I've seen this clue in The Telegraph.

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