1: Go up cedar's first branch (5)
4: Empty cell on mountain? Most ingenious! (9)
10: Old role for paintings that trick the eye (2,3)
12: Ascendant Brazilian city supports church singing group (5)
13: Handle two-thirds of the world (5)
14: Topics I am prepared to make congenial (9)
15: Single parliamentary representative on the Spanish drive (5)
16: Drunk feeding passes to receivers (5,4)
17: Poor man's right to make powerless (9)
20: Plunges about in State's evidence (5)
21: Speaks about actor Alan, a youth (5,4)
22: Warren, they say, is yellow (5)
24: Neil Armstrong initially brought back extraterrestrial (5)
25: Detailed map I sent off (5)
26: Bounder beheaded by slippery swimmer (3)
27: Doctor singes off top of sore and bandages (9)
28: Small room leader of orchestra needed for instrument (5)