I understand that Pabulum no longer contributes regularly but this is a welcome return …The rubric tells us: “4D! 18A/ 3D!” (four words in total) is a quotation from a tale by the author of 9D (three words). Remaining unclued lights give the names of the two protagonists of the tale and that of the 24A in which it was told.
So: 4D, 18A, 3d give us “THE HORROR! THE HORROR!”, the last words of KURTZ (21A) as told by Captain Charles MARLOW (31D) from the YAWL (24A) named NELLIE (26D) in the Heart of Darkness, the 1899 novella by Joseph Conrad who also wrote THE SECRET AGENT (9D) – televised a few years ago with the remarkable Toby Jones in the lead. I found this a tough solve with some obscure words notably those of Caribbean origin. Chambers and a couple of tips from the forum helped out in final stages. Having finally (I hope) parsed everything, I’m in awe of the setter’s erudition.
i am unsure whether the “knots” in the title refers to the various tangles the colonisers get into in justifying colonialism, or to the speed of the yawl, to the misunderstandings between Marlow and Kurtz – or simply to the structure of the crossword itself ….
Across
1. Hot wind from Honduras dogging opponent … (5)
FOEHN
HN (international symbol for Honduras) following (dogging) FOE (opponent). A foehn (or föhn) is a hot dry wind in valleys, especially the Alps.
6 … in the middle of game nursing chocolate bar (7)
BETWIXT
BET (game as a verb) around (nursing) TWIX (chocolate bar). I am unsure why the setter has linked this with 1a …
11 Not a Good Friday rite the New Testament pushed hard (10)
THIRTEENTH
anagram (pushed) of RITE THE NT (New Testament) + H (hard)
13 Earl so rotund cooking thick beef fillet (9)
TOURNEDOS
anagram (cooking) of E (earl) + SO ROTUND
15 Computer component, quartz in the centre (4)
UART
Middle four letters (in the centre ) of QUARTZ. The initials stand for Universal Asynchronous Received Transmitter, a computer component that manages serial communication … if you understand any of that.
16 Flowers strike children with wonder, we hear (7)
ORCHIDS
Homophone (we hear) of AWE KIDS – strike children with wonder
17 Argonaut, say, having only child at school (7)
OCTOPOD
OC (only child) + TO POD (at school). An argonaut is a species of octopus
19 Bent lictor, one smuggling piece of fossil (10)
TRILOBITIC
Anagram (bent) of LICTOR + I (one) around (smuggling) BIT (piece). I spent a long time trying to smuggle MULE into the solution.
27 Noodle a French cook brought in (4)
UDON
UN (a French) surrounding (brought in) DO (cook). A udon is a thick wheat noodle in Japanese cookery
28 Rix’s speciality stuff (5)
FARCE
double definition. The Whitehall farces, staged at the Whitehall theatre were produced by and starred (Lord) Brian Rix, who became a friend of mine and was an executive of Mencap. At one time he was the highest paid artist by the BBC. To farce in cooking is to stuff.
30 Plant sellers in home county Carrie’s man visits (10)
HERBORISTS
HERTS (home county) containing (visits) BORIS (Carrie Johnson is Boris’s current wife). Only when I saw the latter did I give up on herbalists …
33 Expert pruned maple (3)
ACE
ACER (maple) without last letter (pruned)
35 In Karachi, a small intersection (7)
CHIASMA
hidden in KaraCHI A SMAll. A chiasma is an intersection, especially that of the optic nerves.
36 Lord wearing ring and twisted necklace heard to chat lightly in Jamaica (3-4)
OLD TALK
LD (Lord) inside (wearing) O (ring) + TALK (homonym – heard – of torque – a necklace made of twisted metal bands. Old talk is an expression meaning small talk in the West Indies
37 Retired president skinned whale (4)
ORCA
Reverse (retired) of mACROn (President of France) without outside letters (skinned)
38 Make a fetish of slowing down with classy beer one’s getting in (9)
RITUALISE
RIT (slowing down: abbreviation of ritardando in music) + U (classy) + ALE (beer) including (getting in) I’S (one’s)
39 Modesty of various Druses men start to extol (10)
DEMURENESS
anagram (various) of DRUSES + MEN +E (start of control)
40 Influential law officer outside entrance (7)
SWAYING
SG (solicitor general – law officer) outside WAY IN (entrance)
41 Mary Jane almost through street, running smoothly (5)
SWEET
WEE short for (almost) WEED (Mary Jane or pot) inside (through) ST (street)
Down
1 Lawless Tuck oft hide short pieces of rope (7-7)
FUTTOCK SHROUDS
Anagram (lawless) of TUCK OFT + SHROUD (hide) + S (small). Futtock shrouds (I had “threads” for the longest time) are rope, wire or chain links in the traditional rigging of a square-rigged ship … well, who knew that?
2 Quaestor moves in great circles (8)
EQUATORS
Anagram (moves) of QUAESTOR
5 Bill catching fish with help (5)
AIDED
AD (bill) around (catching) IDE (fish)
6 Harper Seven’s sibling somewhere in New York (8)
BROOKLYN
double definition – Harper Seven and Brooklyn are children of David and Victoria Beckham and Brooklyn is a suburb of New York
7 Counsel for Blackbeard (5)
TEACH
double definition – to teach can be to counsel and Edward Teach (or Blackbeard) was a famous pirate
8 We of the Rastamen bringing down a republic (5)
INDIA
I AND I (WE in West Indian dialect) dropping (bringing down) the A
10 Capital jumper clothes unionist – it’s bright orange (6)
ROUCOU
UC (upper case or capital) surrounded by (clothes) ROO (Australian jumper) + U (Unionist. Roucou is annatto, a bright orange colouring. My first version was COU-COU – a West Indian dish made with okra)
12 Choice delicacy thrice daily nibbled (6)
TIDBIT
T.I.D (three times daily in a prescription) + BIT (nibbled). Definition: American version of titbit.
14 Girl from Illinois nut tree shelters (6)
SHEILA
SHEA (African nut tree) around (shelters) IL (Illinois)
20 Old renovated Southsea place with large oven (4,5)
OAST HOUSE
O (old) + anagram (renovated) of Southsea
22 Dan took a meal in the form of rigatoni (6)
TUBATE
TUB (dan: a box or tub for carrying coal) + ATE (took a meal). Rigatoni are tube-shaped pasta
23 Immorality the Devil introduced, German is cutting out (8)
SNICKING
NICK (the Devil) inside (introduced) SIN + G (German)
25 Rocky crevices growing in size or number (8)
CRESCIVE
Anagram (rocky) of CREVICES
29 Edible bulbs mother put in tin (6)
CAMASH
MA (mother) inside CASH (tin). Camash are sweet edible bulbs in the USA
32 Dropsy made European poorly (5)
EDEMA
anagram (poorly) of MADE +E (European). I’ve always spelt this OEDEMA and understood that this was the American spelling but Chambers seems to think it’s kosher …
34 House without corn in Italian resort (5)
CAPRI
Capricorn (house in astrology) without CORN
35 Provide food for four no more (5)
CATER
double definition: to cater is to provide food and CATER is an old word for four (quatre) which survives in dice

One of the best Speccie puzzles of recent weeks I thought.
We were told last year (see the puzzle 2647 “Pabulum’s last bow”) that Pabulum would no longer be setting regularly, but would “continue to appear from time to time”, so it is always welcome to see him. Some may also recall that Pabulum was previously Dumpynose (an anagram of pseudonym) and has been setting for the Spectator since the 90s.
Thanks to Prospero, learning of your connection Brian Rix was a bonus. I can’t come up with any better explanation than yours for the puzzle title.