I got off to a rapid start but it took a long while to finish and get to the bottom of all the parsings.  Thank you Aardvark.
I haven’t checked but this looks like a pangram to me.

| Across | ||
| 1 | COPPER | Metal peeler (6) | 
| double definition – a policeman, slang | ||
| 4 | SWAN SONG | Final appearance of pale lad in middle of Ramsgate (4,4) | 
| WAN (pale) SON (lad) inside ramSGate (middle of) | ||
| 9 | RELIEF | Stand absorbed by official example of sculpture (6) | 
| LIE (stand) inside (absorbed by) REF (referee , an official) | ||
| 10 | PLANKTON | Design keelboat, after vacation, being addicted to marine life (8) | 
| PLAN (design) then KeelboaT (after vacation, contents removed) ON (being addicted to) | ||
| 12 | EZRA | Geezer regularly distributed a religious book (4) | 
| gEeZeR (every other letter, regularly distributed) then A | ||
| 13 | PUSHY | Forward returned up pitch (5) | 
| UP reversed (returned) then SHY (pitch, to throw) | ||
| 14 | MOJO | Magic doctor US soldier heard (4) | 
| MO (doctor) and JO sounds like “Joe” (US soldier) – or you could treat the whole thing as a homophone “MO Joe”, as in “GI Joe” | ||
| 17 | ARISTOPHANES | Greek writer and painter, having first time off work, terribly ashen (12) | 
| ARtIST (painter) missing the first T (time) then OP (work) and anagram (terribly) of ASHEN | ||
| 20 | MAUREEN O’HARA | Hollywood actress’s different aura near home (7,5) | 
| anagram (different) of AURA NEAR HOME | ||
| 23 | AQUA | Water emerging from seaquake (4) | 
| found inside (emerging from) seAQUAke | ||
| 24 | DIGIT | Search Computer World number (5) | 
| DIG (search) IT (the computer world) | ||
| 25 | WAXY | Impressionable character that’s crossed in street (4) | 
| X (a letter or character that’s crossed) in WAY (street) | ||
| 28 | TURNPIKE | American highway staff attending diversion (8) | 
| PIKE (staff) next to (attending, with) TURN (diversion) | ||
| 29 | DAKOTA | Taken aback at fine commercial for aircraft (6) | 
| reversal (taken aback) of AT OK (fine) AD (commercial) | ||
| 30 | SECRETLY | Second tyre burst, with learner inside, behind closed doors (8) | 
| SEC (second) then anagram (burst) of TYRE containing L (learner) | ||
| 31 | STONED | Mick Jagger perhaps joins daughter on a trip (6) | 
| STONE (Mick Jagger perhaps) then D (daughter) | ||
| Down | ||
| 1 | CERVELAT | This Parisian working later eats very small sausage (8) | 
| CE (this, in French, Parisian) then anagram (working) of LATER contains (eats) V (very) | ||
| 2 | POLAROID | One type of exam recalled in school film (8) | 
| I (one) ORAL (type of exam) reversed (recalled) in POD (school, of dolphins perhaps) | ||
| 3 | EWER | Pouring vessel that’s more recent, but not new (4) | 
| nEWER (more recent) missing N (new) | ||
| 5 | WELSH RAREBIT | British shopper obtains fresh Brie to make cheesy meal (5,7) | 
| WELSH (British ?) RAT (shopper, informer) contains (obtains) anagram (fresh) of BRIE | ||
| 6 | NO-NO | In the end, John associating with Yoko is something unacceptable (2-2) | 
| johN (in the end, last letter) then (associating with) ONO (Yoko Ono) | ||
| 7 | OPTION | Theatre event turning into a possibility (6) | 
| OP (operation, an event in a theatre) then anagram (turning) of INTO | ||
| 8 | GUN DOG | Setter maybe loose entering abbreviated definition of horse (3,3) | 
| UNDO (loose) inside (entering) GG (abbreviated definition of horse) | ||
| 11 | PUMPERNICKEL | Before pausing with round piece, grill bread (12) | 
| PUMP (grill, question) follows (before…is…) ER (pausing) NICKEL (a round piece, coin) | ||
| 15 | STRAW | Means to absorb paintings etc back in Cornwall area (5) | 
| ART (paintings etc) reversed (back) inside SW (the Cornwall area) – a drinking straw perhaps | ||
| 16 | DEMON | March winds essentially a beast (5) | 
| DEMO (march) then wiNds (essentially, middle letter) | ||
| 18 | MACAROON | French leader entertains circle, eating a biscuit (8) | 
| MACRON (Emmanuel Macron, French president) contains (entertains) O (circle) all containing (eating) A | ||
| 19 | MARYLAND | Baltimoreans are here to ruin Dylan broadcast (8) | 
| MAR (to ruin) then anagram (broadcast) of DYLAN | ||
| 21 | MANTIS | They’re opposed to touching minute insect (6) | 
| ANTIS (they are opposed to) next to (touching) M (minute) | ||
| 22 | RUBRIC | British in charge follow sport’s guiding rule (6) | 
| BR (British) IC (in charge) follows RU (Rugby Union, a sport) | ||
| 26 | EPEE | European prince outside in estate that’s used to fence (4) | 
| E (European) P (prince) then EstatE (outside in, outer letters of) | ||
| 27 | VAST | Succeeded cutting tax (grand) (4) | 
| S (succeeded) inside (cutting) VAT (tax) | ||
definitions are underlined
I write these posts to help people get started with cryptic crosswords. If there is something here you do not understand ask a question; there are probably others wondering the same thing.
9a How do you get lie from stand?
Spotted the possible pangram and still hadn’t solved 25a. A quick check showed I was still missing an X so WAXY was the obvious answer. Not sure I would have solved this any other way. Guessed CERVELAT which was new to me. Took surprisingly long to get DEMON. Didn’t mind lie = stand. Lie next to and stand next to seem sufficiently close to me.
Thanks to Aardvark and PeeDee.
Michael – both lie and stand can mean to leave alone or leave unchanged. For example in he phrases “let it stand” or “let it lie”.
In my pinion Michae’s right. there’s no way to detect and guess lie from stand.
One of those crosswords where it helps to know ‘stuff’
Thanks to Aardvark and PeeDee
Very entertaining crossword. Learnt a new, for me, sausage. Thanks!
PeeDee – thanks but I would have thought “let it stand” would mean don’t change it whereas “let it lie” implies let it go, drop the subject etc. A fine line perhaps.
9a – ‘stand’ for ‘lie’ is supported by the thesaurus in Chambers Complete Crossword Companion.
5d – ‘British’ for ‘Welsh’ is fine by me. Good clue. I liked 6d NO-NO as well, amongst others.
Thank you Aardvark & PeeDee.
Thanks Aardvark and PeeDee
Only getting to FT puzzles in fits and starts these days as I have a stint at the Times ones (currently working where the Australian newspaper which publishes them about a month later, so thought that I’d try a bit of a variety). This puzzle shows why I do miss the FT ones though.
Found that I eventually ‘knew most of the stuff’ that crypticsue@5 mentions, although CERVELAT was one that I didn’t – must see if I can find and try it. Loved the ‘character that’s crossed’ for X in 25a and thought that the complexity of PUMPERNICKEL was good.
Finished in the centre of the crossword with the actress (which was pleased to finally untangle from the anagram), PUSHY (after getting out of football mode finally) and DEMON (which was quite tricky).