Complete
00:00:00
8 10 13 16 6 5 19 1 17 2 9 14 3 11 15 4 12 18 7
  1. 5 a Coolness under pressure (9)
  2. 8 a Block of ice (4)
  3. 9 a Fixed (8)
  4. 10 a Colourless gas used as fuel, C2H6 (6)
  5. 11 a In a way (4,2)
  6. 13 a Tobacco user (6)
  7. 15 a Ingratiating (6)
  8. 16 a In an earliest stage — evil ramp (anag) (8)
  9. 18 a Rational (4)
  10. 19 a Black tie or smart casual, for example (5,4)
  11. 1 d Skin treatment (4,4)
  12. 2 d Burst into flames (6)
  13. 3 d Bits of uneaten cake — I'm surprised! (6)
  14. 4 d Tree branch (4)
  15. 6 d Regulars — consumers (9)
  16. 7 d Share set aside (9)
  17. 12 d ___ in Blue, 1924 George Gershwin composition (8)
  18. 14 d Prepare for an exam (6)
  19. 15 d Join the ends together (6)
  20. 17 d Gloom (4)

Across

Down