Composer from Britain penning number one (8)
I believe the answer is:
albinoni
'composer' is the definition.
(Italian composer Tomaso Albinoni)
'britain penning number one' is the wordplay.
'britain' becomes 'albion' (I've seen this before).
'penning' means one lot of letters goes inside another.
'number' becomes 'n' (n can represent any number).
'one' becomes 'i' (Roman numeral).
'albion' enclosing 'n' is 'albinon'.
'albinon'+'i'='ALBINONI'
'from' is the link.
(Other definitions for albinoni that I've seen before include "he made notes" , "Italian baroque composer whose famous 'Adagio' was finished by another" , "Tomaso --, Italian Baroque composer" , "Italian composer to whom a well-known adagio was attributed" , "Italian composer; non-alibi (anagram)" .)