Across:
   1. Lack of interest always in the past about route (6)
   4. Ancient kingdom of Crimea has changed (6)
   9. In America Dad finds poisonous tree (4)
  10. Spread of money around state backed by Left (10)
  11. Obedient party has one pound about now (6)
  12. Best to hold crazy nude swinger! (8)
  13. I cure this invalid with this problem-solving approach (9)
  15. Authenticity of cold wine (4)
  16. Ask to settle around centre of Paris (4)
  17. Stalk to hill and kill! (5 4)
  21. He looks for brown singer (8)
  22. Penny is in distorted image of sorrowful flyer (6)
  24. Cool big apple one mother starts selling for nothing (5 5)
  25. Final respects produce tears (4)
  26. Expected to race to English couple’s performance (6)
  27. Cheers abstract artist (6)
Down:
   1. Give consent to wander about after programme (7)
   2. Very musical donkey is a fake? (5)
   3. Unlucky hot secretary returns to the French boat (7)
   5. Avoid embracing new girl (6)
   6. Complicated paper money left behind (9)
   7. Put together a rough broadcast (7)
   8. Present a choir improvising with dancer (13)
  14. Put in order to bring up cooker (9)
  16. 22’s half featherless and black and white (7)
  18. Large sibling has little time inside for absorption (7)
  19. Know his personality partially by a quiet word (7)
  20. Prevent getting a seat in the boat (6)
  23. Strap kit back on square top of howdah (5)
Solution:
=APATHY=MERCIA=
=P=S=A=T=V=H=C=
UPAS=PREVALENCE
=R=A=L=R=D=Q=R=
DOCILE=PENDULUM
=V===S=S=E=E=E=
HEURISTIC=CRED=
===E===C===E===
=PRAY=SHOOTDOWN
=I=R=T=O=S===H=
SEARCHER=MAGPIE
=B=A=W=E=O=I=S=
FANNYADAMS=RIPS
=L=G=R=N=I=T=E=
=DUETTE=ESCHER=
Name: Puzzle 435
Author: by Steve Townsend