ACROSS
 8. DEA DET outside S_ = DEAD SET <bent>
10. <style> HAIRCUT = ↺CHAIR↺ U _T
11. <formality> STATELINESS = (STATE LINES) + _S_
12. DICE - D = ICE <diamonds>
13. A_ I_ O_ L_ I_ = AIOLI <dip>
14. <flip> GO BANANAS = ←BOG← + ANANAS
16. <archipelago> SHETLAND ISLANDS = H inside TIDALNESS* LANDS
18. G LANE outside DO outside ST = GLADSTONE <PM>
20. ←SON ON← = NO-NOS <unacceptable behaviours>
22. <each potter need this> CUE = CU _E
23. <device for signalling> TRANSCEIVER = (SERVER CAN IT)*
25. <amphibian> TADPOLE = TAD POLE
26. INSUL[-t] IN = INSULIN <medication>

DOWN
 1. ODES ←AS← = ODESSA <Ukrainian city>
 2. PARA RE outside MO = PARAMORE <rock band>
 3. <played increasingly fast> STRINGENDO = STRING END O
 4. <archaic pronoun> THEE = THE + _E
 5. <kilted soldiers> PIGS IN BLANKETS = (SAS BELT PINK GIN)*
 6. (ACT 1) ON = ACTION <battle>
 7. <people not believing> ATHEISTS = [-g]AT HEISTS
 9. <expertise> SPECIALISATION = CIALIS inside (TO A PENIS)*
15. →"SOILER BOOT"← = BOILERSUIT <overalls>
16. <wisdom> SAGACITY = SAGA C I T Y
17. (TV ON LOAN)* = NANOVOLT <barely any potential>
19. <fixes> AMENDS = ADS outside MEN
21. <maroon> STRAND <thread>
24. <collude with> ABET = ABE T_