Across:
1 Julius Caesar got rid of juries (‘Julius Caesar’ got rid of ‘juries’ = luscaa = CASUAL) – how flippant is that? (CASUAL),
4 Casual (CARELESS) mini (CAR-) with elegant top (‘elegant’ top = -E-) is reduced (-LESS) (CARELESS),
9 Briefly (d) study (‘read’ without ‘d’ = REA-) issue (issue/offspring = -SON) (REASON) with some common sense (REASON),
10 Open Tequila (‘open ‘Tequila’ = -T-) in tiny bar (tiny bar = BRI-TANY) travelling (= anagram indicator) (BRITTANY) in France (BRITTANY),
12 They act as reminders to the kitchen staff (EGG TIMERS) of the early bird (EGG) and the ones that tend to go off? (TIMERS) (EGG TIMERS),
13 Pole (North Pole = N-) only (only = -YLON) makes a mess (= anagram indicator) (NYLON) of material (NYLON),
14 Conference (TALK) after (= position indicator) 4 across (‘careless’ = CARELESS) (CARELESS TALK) could cost lives according to British wartime propaganda (Second World War poster: “CARELESS TALK costs lives”),
18 From the start, 14 across (‘careless talk’ = CARELESS-) opens never-ending story stupidly (opens ‘never ending story stupidly’ = -NESS) (CARELESSNESS) out of negligence (CARELESSNESS),
21 Boredom (ENNUI) is central to French (central to ‘French’ = EN-) university (National University of Ireland = -NUI) (ENNUI),
22 Start a fight (SEE ACTION) – is that the view of the war correspondent? (SEE ACTION),
24 Ran to ground (CORNERED) in Ring (CORNER- in boxing ring) by journalist (-ED) (CORNERED),
25 Popular (IN-) type from The Den (-CUB-) and one (-I) (INCUBI) of those responsible for A Scare at Bedtime perhaps (INCUBI),
26 Sounds like somewhere one could find jumpy characters (“para site” = “PARASITE”) – one living off the other (PARASITE),
27 Cop taken from Princeton (‘cop’ taken from ‘Princeton’ = rinetn = INTERN) jail (INTERN).
Down:
1 Exchanged notes (CURRENCY) in Vogue, almost (‘current’ almost = CURREN-) fairly (half of) racy (half of ‘racy’ = -CY) (CURRENCY),
2 Goes from pub to pub (STAGGERS) to put on a show (stage = STAG-E-) involving legend (‘leg’ end = -G-) and sister (Sr) making a comeback (= reversal indicator) (Sr = -RS) (STAGGERS),
3 Socialite dismisses sect (‘socialite’ dismisses ‘sect’ = oiali = AIOLI) as a saucy type (AIOLI),
5 Middle class (middle ‘class’ = A-) angry (-CROSS) in area with salty water (THE SEA) (ACROSS THE SEA) over in England (ACROSS THE SEA),
6 Makes sense of the convolutions (ENTANGLES) in 10 (ten = ENT-) new (= anagram indicator) viewpoints (-ANGLES) (ENTANGLES),
7 Give the green light to (ENABLE) remove lint from table linen (remove ‘lint’ from ‘table linen’ = abelen = ENABLE),
8 Having a look behind the curtain (snooping = SPYING) – that’s a job for the agency (job for CIA agency / SPYING),
11 English (-E-) judge (-ASSESS-) contacts workers (-MEN-) in retweet (R-T) (REASSESSMENT) for another view of the same material (REASSESSMENT),
15 Typical of the vinegar seeping through the bag (LEAKINESS) for a (-A-) family (-KIN-) getting last single (last single = -E-) in Takeaway (L-ESS) (LEAKINESS),
16 Footy treatment (PEDICURE) of rude epic (rude epic = PEDICURE) novel (= anagram indicator),
17 A (A-) star (-SUN-) from club (-C-) is charged (-ION) (ASUNCION) in South American capital (ASUNCION = capital of Paraguay),
19 Most of the players (most of the ‘team’ = TEA) take trophy (CUP) (TEA CUP) to part of China (TEA CUP),
20 You won’t hear him if you’re asleep (SNORER) or sound asleep? (SNORER),
23 Cash in on his missing (‘cash in on’ ‘his’ missing = canon = CANON) list of quality books (CANON).