Across
1 US president with comparatively small primate (8) BUSHBABY
5 Ambassador on at head of embassy (6) LEGATE
10 Star and co-stars he’ll cast in part of theatre (9,6) ORCHESTRA STALLS
11 Rings back to express disdain (4-4) POOH-POOH
12 Giant pheasant (5) ARGUS
14 Missile’s power staggered sailor (7) POLARIS
16 Device that spins back and forth (7) ROTATOR
17 Strange noises linked to opening of special sitting (7) SESSION
19 Obsessive enthusiast meeting old actor? Hazel, perhaps (3-4) NUT-TREE
21 Do exam again, one among the others (5) RESET or RESIT
22 Rack was knocked over by animal (8) SAWHORSE
25 Bird in rifle range once shot by foremost of pistoleers (9,6) PEREGRINE FALCON
26 King’s terrible dread about onset of war (6) EDWARD
27 Veteran soldier in TA, slowed remarkably (3,5) OLD SWEAT
Down
1 Mostly obstruct coalition (4) BLOC
2 Disgusted by old pervert (5) SICKO
3 Idle talk from bishop, first to leave there drunk (7) BLETHER
4 Pantomime character’s single error? Keeps quiet (7,4,3) BUTTONS ONE'S LIP
6 Withdraw from other court (7) EXTRACT
7 Reptile snapped at gorilla (9) ALLIGATOR
8 Financial security obtained by a setter? Yes, oddly (4,6) EASY STREET
9 Girl with rat producing a firework (9,5) CATHERINE WHEEL
13 What’s always held by Sotheby’s? (10) APOSTROPHE (nice one)
15 Laws start to be broken in the end? (4,5) LAST STRAW
18 A whole number, for example, located in Bury? (7) INTEGER
20 Hard-working types, twenty-four at each end, with Jason, at sea (7) TROJANS
23 Plinth about to be taken in by individual (5) SOCLE
24 Shore bird in difficulty (4) KNOT