A puzzle from Brunel that fits the ‘serious daily cryptic’ definition pretty well, I thought.
Abbreviations
cd cryptic definition
dd double definition
cad clue as definition
(xxxx)* anagram
anagrind = anagram indicator
[x] letter(s) removed
definitions are underlined
Across
1 “My shout,” Isaac admitted
CRIKEY
An insertion of IKE in CRY. The insertion indicator is ‘admitted’.
4 One’s wearing amulet with a power to inspire
CHARISMA
An insertion of I’S for ‘one’s’ in CHARM, followed by A. The insertion indicator is ‘wearing’.
9 Writer rings Oxford University lecturer about composer
POULENC
An insertion of OU and L in PEN, followed by C for circa or ‘about’. The insertion indicator is ‘rings’.
11 Send out judge to collar a policeman
RADIATE
An insertion of A and DI in RATE. The insertion indicator is ‘to collar’. Plenty of insertions so far.
12 Reserve in backward old tribespeople
ICENI
A charade of ICE and NI reversed. The tribe best known for their revolt under Boudica against the Romans, which was ultimately unsuccessful.
13 He’s making eyes at our Lucy, oddly, is Dicky
OCULARIST
(AT OUR L[U]C[Y] IS)* with ‘Dicky’ as the anagrind.
14 Stylish lady in small city
CHICHESTER
A charade of CHIC and HESTER.
16 Time is swift, maybe
BIRD
A dd. Got to be a specific BIRD for an OPBL, I’m afraid.
19 O love, I forgot to mention … oh dear …
OOPS
A charade of O, another O and PS for post scriptum.
20 Being quick with going for oxygen, see a doctor first
ADROITNESS
Brunel is inviting you to remove the W for ‘with’ from WITNESS for ‘see’, replace it with O for ‘oxygen’ and precede all that with A and DR.
22 Warrant ordered to arrest OJ – long battle results
TROJAN WAR
An insertion of OJ in (WARRANT)* The insertion indicator is ‘to arrest’ and the anagrind is ‘ordered’.
23 Senses opportunity to return incomplete models
POSES
Hidden reversed in SenSES OPportunity.
25 More scrumptious stunner has sex on rebound
TASTIER
An insertion of IT reversed in TASER. The insertion indicator is ‘has’.
26 Drugs rumoured to accompany gin, possibly, in swinging bar
TRAPEZE
A charade of TRAP for ‘gin’ and EZE, aural wordplay for Es, the drugs.
27 Treasure Island viewer?
SPYGLASS
A cd.
28 Put in order – right old idiot’s got order wrong way round
ASSORT
A reversal in order of RT, O and ASS.
Down
1 Lively piece about Chief Information Officer supporting reduced cost
CAPRICCIO
A charade of CA for circa for ‘about’ (again), PRIC[E] and CIO. The ‘supporting’ tells you that CIO is the final element in a down clue.
2 Recalled vehicles unit only partly operational
IN USE
Hidden reversed in vehiclES UNIt.
3 Brunel offers quote in hearing, making sense
EYESIGHT
Aural wordplay for I CITE, with Brunel being the setter, of course.
5 Using hard clue, tire poor, confused solver
HERCULE POIROT
(H CLUE TIRE POOR)* with ‘confused’ as the anagrind. Agatha Christie’s detective.
6 Screw up and plan again
REDRAW
A reversal of WARDER, for which ‘screw’ is slang.
7 Setter and Elsie, seen regularly together, initially go steady
STABILISE
A charade of STAB for ‘go’, I for the ‘setter’ and eLsIe SeEn.
8 What might be amber beer, served at right temperature
ALERT
A charade of ALE, R and T. A timely clue, since today much of England is under an amber alert for heat.
10 Argued with X suppressing speech by Miliband perhaps
CROSSED SWORDS
A charade of X for CROSS and EDS WORDS. You have to read ‘suppressing’ as ‘holding down’ in a down clue to give you the order of the particles.
15 Arrogantly cutting queen, very disrespectfully
IMPIOUSLY
IMP[ER]IOUSLY
17 Cover version of the duets succeeded
DUSTSHEET
(THE DUETS S)* with ‘version of’ as the anagrind. S for ‘succeeded’ is in most dictionaries and refers to, for example, regal succession.
18 Mounting disputes about old postal service providing interim solutions
STOPGAPS
An insertion of GPO in SPATS, all reversed (‘mounting’, since it’s a down clue). The insertion indicator is ‘about’.
21 A German boy’s taken recalled book
DANIEL
An insertion of EIN for one of the German words for ‘a’ in LAD, all reversed. The insertion indicator is ‘[ha]s taken’. A book of the Old Testament.
22 They’re short on stage 4 components, reportedly?
TUTUS
Aural wordplay (‘reportedly’) for TWO TWOS, which make four.
24 Deal with phone company during brief stay
SEE TO
And a final insertion, of EE in STO[P]. The insertion indicator is ‘during’.
Many thanks to Brunel for today’s Indy puzzle.

For 15d, I took the definition as “very disrespectfully” and parsed as IMP(ER)IOUSLY. In 14a, the lady needs to be Hester.
Very tricky indeed. Took a while to get going but nearly finished without help. Used a word fit to get TUTUS (nice clue) & STABILISE.
You are right, Hovis – thank you. I have corrected the blog.
4a I took I’S for “one’s”, because the m is used in CHARM. Found this a tough, but very satisfying, challenge. Needed the blog for a few parsings (13a, 7d, for example), so thanks to Pierre. Nice to see Poulenc get a mention. And loved TUTUS – best of a good lot. Thanks Brunel
Thanks both. A struggle, but I got there unaided, if not fully parsed, including the Yoda inspired ADROITNESS. Given DANIEL is clued simply as book, and Hester as lady – I’ve never known one in 60 years and counting, but maybe they all live in CHICHESTER, our setter was putting up a fight. CRIKEY took an age, as I didn’t know that Ike can be a shortening of Isaac – does not apply to the former president, nor the loveable shopkeeper in The Waltons.
Thanks Pierre and Brunel.
First time solving a Brunel puzzle.
Quite difficult, including three not fully parsed. Thanks for clearing them up.
Yet, quite liked it. Will watch for his (yes, I know) next.
HERCULE POIROT, TROJAN WAR and TUTUS stood out.
9a Poulenc could have the wrong definition.
Poulenc was a composer not a writer and ‘pen’ was already used in the parsing – my parsing works the same.
Really enjoyed today. Thanks both. Seemed to be on the right wavelength albeit with some help. HERCULE POIROT was favourite – and CROSSED SWORDS.
PS Glad to see those annoying political adverts have stopped