Breakdown of French cable system (7)
I believe the answer is:
debacle
'breakdown' is the definition.
(debacle is a kind of breakdown)
'of french cable system' is the wordplay.
I cannot really understand how this works, but
an anagram of 'cable' is 'ebacl' which is present in the answer.
'of french' could be 'de' ('of' in French) and 'de' is present in the answer.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for debacle that I've seen before include "A sound defeat" , "Humiliating failure" , "A complete collapse or messy failure" , "Utter disaster" , "Sudden and violent collapse" .)