1: Fruit found in Carmel only (5)
4: Oil depots destroyed ocean habitats (4,5)
8: No one told sister (3)
9: Sound practical perception is a normal feeling (11)
11: European sage knew a novel novel (9,4)
13: Tar mess contaminated rivers (7)
15: How might number mine something? (5)
18: Rooted in regressive muddleheaded isolation (5)
19: Treason destroyed Washington insider (7)
21: Modernise rear, in the opinion of escort (5,2,2,4)
23: Fancied poem composed in comfort (5,2,4)
25: Choose to take the top off (3)
26: Avoids seeds, pits, nuts (9)
27: Assessor is ignoring every other great theory (5)