ACROSS
 1. <pirate> PLAGIARISE = LAG I inside PARIS _E
 6. ←BIRCH← - _H_ = CRIB <residence>
10. M ETA inside NAG = NAME TAG <ID>
11. <wear> CLOBBER <belt>
12. <daisy> OXEYE = OXY E outside E
14. <amateur> LAYPERSON = (PLAYERS, P→) O N
15. "TIE TEE WHY TEASE" = TIGHTY-WHITIES <underwear>
18. <gold granules> DEMERARA SUGAR = ←RAGUSA + RARE MED←
20. _A LONG SIDE = ALONGSIDE <with>
22. ENE + MY = ENEMY <competition>
23. <were> EXISTED = EXITED outside _S_
24. <huntsman made animal> ACTAEON = ACT A ONE*
26. <some people> THEY = (THE Y)
27. <these manually immobilise> HANDBRAKES = →"BRAND HAKES"←

DOWN
 1. (PIN IT ON) - _T = PINION <wing>
 2. _A RM = ARM <outfit>
 3. <collectively> IN THE AGGREGATE = GATHERING* E GATE
 4. <Internal Affairs perhaps> REGULATOR = ←ROTA LUGER←
 5. S KENTUCKY - KENT = SUCKY <poor>
 7. ROBE + SPIER RE = ROBESPIERRE <revolutionary>
 8. <lady> BARONESS = BAR[-it]ONE SS
 9. RINGLET inside COVETER = COVERING LETTER <explanatory note>
13. _E _X (TEMPO RISE) = EXTEMPORISE <play it by ear>
16. STELA inside WAND = WASTELAND <desert>
17. <next> ADJACENT = (A DJ A CENT)
19. <one soporific> HYPNOS = "HIP" NOS
21. <speaking in code, I> INDIA = IN ←AID←
25. <buglers> ELK = (.l)EL K(e.)