PHSSTHPOK kicks off the week…
A very enjoyable puzzle, though a bit more of a challenge than usual for a Monday morning.
Thanks PHSSTHPOK!

ACROSS
1. Permit those finally excluded before sixteen, for example, to vote (8)
SUFFRAGE
SUFF[e]R (permit, [thos]E (finally) excluded) before AGE (sixteen, for example)
5. Plaster minor injuries around clot unevenly (6)
STUCCO
(CUTS)< (minor injuries, <around) + C[l]O[t] (unevenly)
9. Ticks example broadcast (8)
INSTANTS
“instance” = INSTANTS (example, “broadcast”)
10. Cheers, episode nine: Crane openly ridicules European capitals (6)
ENCORE
E[pisode] N[ine] C[rane] O[penly] R[idicules] E[uropean] (capitals)
12. Sucker punch, no joke, gets past protection (5)
LEECH
[pun]CH (no PUN (joke)) gets past LEE (protection)
13. Economy Ministry traffic follows what is expected (9)
PARSIMONY
SIMONY (ministry traffic) follows PAR (what is expected)
14. Sound quality pioneered by soprano (6)
STRAIT
TRAIT (quality) pioneered by S (soprano)
16. It marks the spot General is picked up and run over (7)
EXPLAIN
“X (it marks the spot) + PLANE (general)” = EXPLAIN (“picked up”)
18. Try Tetris, mostly replaced by debut of Nintendo console (7)
HEARTEN
HEAR (try) + TE[tris] (mostly replaced by) N[intendo] (debut of)
20. Court library is vacant (6)
WOODEN
WOO (court) + DEN (library)
22. Some gains are realised from contents of stolen gilts (3-6)
ILL-GOTTEN
([s]TOLEN GILT[s] (contents of))* (*realised from)
23. What cow does with English deer (5)
MOOSE
MOOS (what cow does) with E (English)
24. Striking gesture (6)
SIGNAL
25. Blend fuel Tesco giving away to add energy (8)
COALESCE
COAL (fuel) + [t]ESC[o] (giving away TO) + E (energy)
26. Shrink accompanying medical facility (6)
WITHER
WITH (accompanying) + ER (medical facility)
27. Immoral and lacking heart — moral on the outside (8)
DECADENT
A[n]D (lacking heart), DECENT (moral) on the outside
DOWN
1. The Spanish attack Sweden, lifting blockade (6)
STIFLE
(EL (the, Spanish) + FIT (attack) + S (Sweden))< (<lifting)
2. Can’t travel so amazingly far at this length (6,4,5)
FASTER THAN LIGHT
(FAR AT THIS LENGTH)* (*amazingly)
3. Get to stretch (5)
REACH
4. Won work with last two pieces of apricot crumble (2,2,3)
GO TO POT
GOT (won) + OP (work) with [apric]OT (last two pieces of)
6. One plays spin or net shot (6,3)
TENNIS PRO
7. Pudding cooked in the Colosseum with coal after lira abolished (9,6)
CHOCOLATE MOUSSE
(THE COLOSSEUM with COA[l] (after L (lira) abolished))* (*cooked)
8. How 11 is written gradually (3,2,3)
ONE BY ONE
Double (cryptic) definition
11. 3 down by hard box or plane, perhaps (4)
TREE
T[h]REE (3, down by H (hard))
15. Instrument built from gold I removed from laboratories (9)
ASTROLABE
(LABORAT[ori]ES (OR (gold) + I removed))* (*built from)
17. Washington rose up after enslavement as tool (8)
CHAINSAW
(WA)< (Washington, <rose up) after CHAINS (enslavement)
19. Crazy for students to adopt ChatGPT’s conclusion (4)
NUTS
NUS (students) to adopt [chatgp]T (conclusion)
20. Charming ladies wear fashionable silk top (not new) (7)
WINSOME
WOME[n] (ladies, not N (new)) wear (IN (fashionable) + S[ilk] (top))
21. Heads of major economies invested in small dollar denomination bond (6)
CEMENT
M[ajor] E[conomies] (heads of) invested in CENT (small dollar denomination)
23. Animal tallow extract in Mediterranean island (5)
MALTA
[ani]MAL TA[llow] (extract)
Agree this was tricky but some vg clues, notably faster than light.
Slight moan at 10a: most of them are initials but not capitals. Does this get me life membership of the Society of Pedants?
Thanks both.
I do enjoy Phssthpok crosswords for the main part, due to some unusual clues that exercise the old brain matter. There are always clues where the definition is unusual, at least to me. I would think of ‘stifle’ as ‘block’ rather than ‘blockade’; not sure I would ever equate ‘wooden’ with ‘vacant’ (a wooden expression perhaps?), or ‘den’ with ‘library’ for that matter.
As I type this, PostMark hasn’t made an appearance so I feel I should comment on 20d. You wear things on the outside not the inside so INS is wearing WOME(n), not the other way around.
PARSIMONY made me smile when I realized what the ministry traffic was; almost a fusion as my first thought was to separate the two words. I always struggle to get “wearing” the right way round. I wondered if WOODEN was going to be WOOLLY but there was an extra l and vacant was doing double duty.