New Town theory, remarkable (10)
I believe the answer is:
noteworthy
'remarkable' is the definition.
('noteworthy' can be a synonym of 'remarkable')
'new town theory' is the wordplay.
'new' is an anagram indicator.
'town'+'theory'='towntheory'
'towntheory' is an anagram of 'NOTEWORTHY'.
(Other definitions for noteworthy that I've seen before include "Interesting, significant" , "Of significance" , "important" , "Signal" .)