Freedom of the Island (7)

I believe the answer is:
liberty
'freedom' is the definition.
(liberty is a kind of freedom)
'the island' is the wordplay.
I cannot really understand how this works, but
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is present in the answer.
'island' could be 'i' (geographical abbreviation) and 'i' is found in the answer.
This explanation may well be incorrect...
'of' acts as a link.
Can you help me to learn more?
(Other definitions for liberty that I've seen before include "Act of undue intimacy" , "Right" , "Freedom from slavery" , "cheek" , "Independence" .)
