Compulsory cover (7)

I believe the answer is:

binding

I believe this is a double definition.

'compulsory' is the first definition.
(thesaurus)

'cover' is the second definition.
(thesaurus)

(Other definitions for binding that I've seen before include "Mandatory" , "work for a bookmaker" , "Obligatory" .)

I've seen this clue in The Telegraph.

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