Across:
   1. Core belief of Stalin unravels after good-time girl begins moving (14)
   9. Smelly stuff found in the morning in new porch (7)
  10. Spread gruel on artist’s back as usual (7)
  11. Band left study of the past (5)
  12. Oratorio composed about Divine Leader for film (4 2 3)
  13. Sailor is in Cathy’s new crew (9)
  14. Picture within chamber is burning! (5)
  15. Hear about northern ex-Taoiseach (5)
  17. Pompous brag about doctor at the top (9)
  20. A hot time in 2000? (9)
  22. Can brute kept inside make harmful substance? (5)
  23. Swimmer ran back with prince (7)
  24. Reduce journey (7)
  25. Spray seed and tear after miniscule payment (10 4)
Down:
   1. Confronting Conservative fellow member within intensive agri-business (7 7)
   2. I’d moan about cold when travelling (7)
   3. King Tut’s Dad gets taken out carrying female article (9)
   4. Murder a bad listener! (7)
   5. The man leaves here in coach to find land... (7)
   6. ...Fair land (5)
   7. Place where Ronseal is mixed? (7)
   8. Force Pop on to FC ground as a demonstration (5 2 7)
  14. Naturalist’s scheme involves insects beginning to multiply (9)
  16. Shifting reeds on back (7)
  17. Bottom line about British queen as one who lacks confidence, maybe (7)
  18. Croc swims into low country (7)
  19. Feel divorcee is in utter mess! (7)
  21. Out of university with no hopeful individual prospects initially (5)
Solution:
FUNDAMENTALISM=
A=O=K=A=E=I=A=P
CAMPHOR=REGULAR
T=A=E=D=R=H=E=O
OLDEN=ROADTORIO
R=I=A=U=I===N=F
YACHTSMAN=PHOTO
F===E=====L===F
AHERN=BOMBASTIC
R=N===U=O=N=E=O
MIDSUMMER=TOXIN
I=O=N=B=O=S=T=C
NARWHAL=COMMUTE
G=S=I=E=C=A=R=P
=PEPPERCORNRENT
Name: Puzzle 423
Author: by Steve Townsend