Across

1 Discretion keeps one silent (5)

4,18 Biblical flower grew in front of Old French girl (4,2,6)

9 Shrewd messenger is in northern Russia (9)

10 One awfully nice tribe (5)

11 Predicament with t’other son out to make wedding pledge (6,4,5)

12 Leave scene of temptation (6)

14 Let Da see around river valley (8)

16 Heretic very agitated with explosive energy (8)

18 See 4 across

21 Anglicans following His Grace initially round channel haphazardly (6,2,7)

24 Man retains a means of communication (1-4)

25 Church may have this shouter — tenor needing to be restricted (4,5)

26 Find 50 at cathedral in the recent past (6)

27 A bishop, a saint in French city (5)

Down

1 Vehicle has little power? Walk! (5)

2 Do in Channel Islands plants (5)

3 Guide has drink with American actress (7)

4 Fifty-one abandoning faith in part of the country (6)

5 Joined and fought no one (8)

6 After work I consumed special drugs (7)

7 Elegant society girl broadcasting (8)

8 Complete number for course certificate (8)

12 Calm does dissipate for one threatened by sword (8)

13 Strange individual (8)

15 Currency has initial loss after communist increase (8)

17 Saint in church with hairy bits (7)

19 After audible greeting eat fancy meal (4,3)

20 You and I, knowing about English preacher (6)

22 Inexperienced army overturned in conflict (2,3)

23 Girl in party getting sir upset (5)