I managed to sneak in a little under the 30-minute mark when the spacey clue finally fell, though I was about as bemused by the parsing as I am by the whole idea that it is somehow edifying or vaguely useful to send metal tubes into the heavens!
ACROSS
1 Conclusion after day teaching? Sack third of team (9)
DEDUCTION – D EDUC[a]TION (A is the third letter of teAm)
6 Unbuttoned daughter in college departs (5)
UNDID – D in UNI D
9 Following Mrs Thatcher is a flabby man with gifts (6,9)
FATHER CHRISTMAS – F + anagram* (‘flabby’) of MRS THATCHER IS A. Super clue!
10 Zulu comes after this Union soldier (6)
YANKEE – In the NATO phonetic alphabet, ZULU comes after YANKEE
11 Backward old man with right hand covered in glass fragments (8)
SHRAPNEL – PA RH in LENS all reversed
13 Wife longed to stop boy with it (8,2)
SWITCHED ON – W ITCHED in SON
14 Group of backsliding yobs arrested — breaking this? (4)
ASBO – hidden in the middle there somewhere…
16 Spots hole in one stuffed with note (4)
ACNE – N in ACE (a golfing hole-in-one)
17 Study the author’s diary hidden in beam (10)
MINERALOGY – MINE (the author’s) LOG in RAY
19 Exciting item in one’s current account? (8)
ELECTRIC – I think I may require the aid of the sciency types here, as, unless the final five words of the clue are merely gesticulating Magnus Pyke-like in the vague direction of an electrical context via CURRENT, I am well and truly flummoxed
20 Willing to mix upper-crust elements to obtain firm backing (6)
SOCIAL – this sciency clue completely passed me by, as I didn’t bother to parse it, having spotted the reversed company (I think like a speed-solver, you know; yes, I do, stop tittering!); for the record, it is CO reversed in SIAL (‘the silicon-rich and aluminium-rich rocks of the earth’s continental upper crust, the most abundant individual rock being granite’ – thanks, Collins)
23 In China, The Tempest or Much Ado About Nothing? (1,5,2,1,6)
A STORM IN A TEACUP – I think this works as follows, if I am right in thinking that one needs to underthink this rather overthink it: if you have a tempest in a piece of china, you might call it a storm in a teacup. I also think that you can account for the change from THE tempest to A storm by invoking the use of indefinite A (as well as definite article THE) to operate generically in phrases of the type, ‘Tigers are mammals’ /’The tiger is a mammal’ / ‘A tiger is a mammal’. Did I really underthink that?
24 Solemnly proclaim death of king and his mistress (5)
KNELL – K NELL [Gwyn – actress and Welshish mistress of CRII]
25 This, wasting time, spider mite frantically chewed? (9)
EPIDERMIS – SPIDER[t]IME*
DOWN
1 Film duck at full volume in 24 hours (5)
DAFFY – FF (musical notation) in DAY
2 Jug suggests name for top medical specialism (9,6)
DETENTION CENTRE – a JUG is slang for a prison but I’m not sure how to get there (besides robbing a train). Is TOP an oblique reference to one’s head and does DETENTION represent ‘de-tension’, and is a centre synonymous with a specialism? So many questions…And the answer is: the centre of detENTion is a common medical specialism. A somewhat involuted clue
3 Trust 100 Anglicans to conserve river garden (8)
CREDENCE R EDEN in CE-
4 This isn’t Long Island! (4)
INCH – double definition
5 Old PM right to change direction regarding a state (5,5)
NORTH KOREA – NORTH (British PM of yore) OK reversed RE (regarding) A
6 Throw drink during pursuit of Cockney? (6)
UNSEAT – SEA (drink) in ‘UNT (as in ‘unt the thimble, awight?!)
7 Perform less very old British music played in salutation (7,8)
DOMINUS VOBISCUM – DO MINUS V O B MUSIC*
8 Casual young leader excited about enlisting officer (9)
DESULTORY – reversal of Y (the leading letter in Y[oung]) ROUSED around (‘enlisting’) LT (officer)
12 Conclusive final absorbs four (10)
DEFINITIVE – IV in DEFINITE
13 Love letters sent round with due respect to — EVA! (9)
SPACEWALK – PACE (‘with due respect to’) in SWALK (acronym of Sealed With A Loving Kiss – something I am proud to say I’ve never used or heard of). Anyone who can call a spacewalk ‘extravehicular activity’ needs to read Out of the Silent Planet. Or any poem…
15 Colouring‘s routine in type of sugar (8)
CAROTENE – ROTE in CANE
18 Many standing up to drink monarch’s alcohol (6)
STEROL – ER in LOTS reversed
21 Possibly, first Roman wet nurse‘s disease? (5)
LUPUS – A wolf suckled Romulus and Remus, and LUPUS is a chronic disease of the immune system
22 Slalom round a Munro (4)
SAKI – A in SKI; Hector Hugh Munro published his stories as SAKI
Festive music: Bach’s Christmas Oratorio
Merry Christmas 🙂