1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27

Across

  1. 1
    Ordered fireman to preserve world heritage site (7,2,3)
  2. 9
    Noble matter (5)
  3. 10
    Ruddy stag party members start to arrive in Irish town (9)
  4. 11
    Porn content extended to go beyond agreed limit (7)
  5. 12
    Beast in beret's no musical backing (7)
  6. 13
    Sort of fields amongst high waters by rivers (10)
  7. 15
    Spot? Yes, essentially a mole (4)
  8. 18, 22
    "Father, we have sinned" — last two leaving one of the Orkney Islands (4,7)
  9. 19
    Jumbo crossword compilers? They're often 5 (3-7)
  10. 22
    See 18
  11. 24, 20
    Repair of these second houses still to be detailed in expense accounts (7,6)
  12. 25
    Concession from NATO? For one, that hurt (9)
  13. 26
    Letter from Greece returning share in full (5)
  14. 27
    Play set in ultimately the worst off part of London (5,7)

Down

  1. 1
    Timid person tentatively starting to blame inferior cheese (9)
  2. 2
    Hazel's cooking won't burn (8)
  3. 3
    Ex-PM reading book in shower? (5)
  4. 4
    TV scores for skiing moves (9)
  5. 5
    Hurried up? (6)
  6. 6
    Playing Real, gets little time on the ball (5)
  7. 7
    Type of clue with answer X (6)
  8. 8
    Pretty mechanical? Just Bottom, enthralled by Puck, perhaps (6)
  9. 14
    All in? Completely! (5,4)
  10. 16
    Some of those 5 get led astray? What a pity about that (9)
  11. 17
    Pose as model in topless play (8)
  12. 18
    Fruit women put in babyfood as winter starts (6)
  13. 20
    See 24 across
  14. 21
    Be a surfer, initially wearing surprisingly sober clothes (6)
  15. 23
    Bombardment of note across area 11 by 5 (5)
  16. 24
    Some "yards per minute" swimmers (5)