A government department of note (8)
I believe the answer is:
treasury
I believe this clue is a double definition.
'a government department' is the first definition.
(I know that treasury is a type of government department)
'note' is the second definition.
(thesaurus)
'of' is the link.
(Other definitions for treasury that I've seen before include "Exchequer - store for valuables" , "Government department in charge of finances" , "Its valued contents" , "Government finance department" , "British government department managing finances" .)