Across:
8 Bug (CICADA) in police department (CID = CI-D) captures assistant commissioner (Assistant Commissioner = AC) backtracking (= reversal indicator) (AC = -CA-) on answer (-A) (CICADA),
9 A (A-) priest (parish priest = -PP-) writing (from the 3Rs = -R-) track (-OVAL) (APPROVAL) for Confirmation (APPROVAL),
10 Take a part (take apart = UNDO) setting up (= reversal indicator) in neighbourhood nursery (in ‘neighbourhoOD NUrsery’ = odnu = UNDO),
11 Retires (-NAPS) after (= positional indicator) sweeteners (sugars = SUGAR S-) (SUGAR SNAPS) supplied by the vegetable man (SUGAR SNAPS),
12 Plant (CASSIA) with dope (-ASS-) taken in by agency (C-IA) (CASSIA),
14 Particular (SPECIFIC) epics (epics = SPECI-) adapted (= anagram indicator) by figurehead (‘Figure’ head = -F-) in charge (-IC) (SPECIFIC),
15 For religious reasons, it was established by our neighbours (Established Church = CHURCH OF ENGLAND) as a mass medium (a Mass medium = CHURCH) for old French (Old French = OF) country (ENGLAND) (CHURCH OF ENGLAND),
18 They take over (USURPERS) from loan sharks (usurers = USUR-ERS) around port (-P-) (USURPERS),
20 Trees taken from supermarket (‘trees’ taken from ‘supermarket’ = uprmak = MARKUP) for profit (MARKUP),
22 Silent (silent = TINSEL-) treatment (= anagram indicator) from Shannon, for instance (-TOWN) (TINSELTOWN), in Hollywood (TINSELTOWN),
24 Local curiously has a look around (NOSE) part of the plane (NOSE),
25 Siege can (siege can = AGENCIES) damage (= anagram indicator) the levers of American government (AGENCIES),
26 Nothing rare in air letters (nothing ‘rare’ in ‘air letters’ = iletts = TITLES) from a number of different addresses (TITLES).
Down:
1 Venetians set off (‘Venetians’ set ‘off’ / without ‘set’ = venian = VIENNA) from European capital (VIENNA),
2 Concealed beyond a doubt (concealed ‘beyonD A DOubt’ = DADO) what divides upright types in The House (DADO rail divides uprights/walls),
3 Chap says (chap says = PAYS CASH) doctor (= anagram indicator) doesn’t get any credit (PAYS CASH),
4 Took to Twitter (took to twitter like a bird = SANG) consumed by bipartisan grievance (consumed by ‘bipartiSAN Grievance’ = SANG),
5 Press a (press a = SPARSE) novel (= anagram indicator) in short supply (SPARSE),
6 Short (t), bloodthirsty type (‘Count’ Dracula = ‘count’ without ‘t’ = COUN-) got cold (-C-) and got sick (-ILL-) – otherwise (-OR) (COUNCILLOR) he should be in office (COUNCILLOR),
7 Take part in 16 down, for instance (CAMPAIGN in ‘hustings’), as a course of action (military CAMPAIGN),
13 Nearly (e) certain (‘sure’ without ‘e’ = SUR-) initial planning (initial ‘Planning’ = -P-) for Easter 1916 (-RISING) (SURPRISING) not predictable (SURPRISING),
14 Knock back (= reversal indicator) bottles of Mimosa, Fosters (bottles of ‘mimoSA, FOSters’ = safos = SOFAS) and popular types in the lounge (SOFAS),
16 Nights (nights = H-TINGS) travelling (= anagram indicator) around America (-US-) (HUSTINGS) to political meetings (HUSTINGS),
17 Mention a (mention a = NOMINATE) play (= anagram indicator) to recommend (NOMINATE),
19 Serves up (= reversal indicator) a fair amount (half of) of the lentil dish (half of ‘dhAL’ = al = -LA-) surrounded by rice (rice = EC-IR) (ECLAIR) in choux pastry (ÉCLAIR),
21 Poor (= anagram indicator) result (result = ULSTER) for Leinster neighbour (ULSTER),
23 Remove from office (OUST) piece of spurious technology (piece of ‘spuriOUS Technology’ = OUST),
24 Take cognisance of (NOTE) what’s in Filipino temple (what’s in ‘FilipiNO TEmple’ = NOTE).