Across
Underground enthusiasts heading for certain states (6)
Flowering plant’s trouble: kept regressing (6)
I haven't cracked this one yet — but Fifteensquared have:
( AIL [trouble] + HAD [kept]) all reversed (regression)
Mechanic and master at work (9)
Calls round to meet saint (5)
Bede perhaps coming in to read a manuscript (4)
Public transport lines filling routes by going all over the place (10)
Tried for better position Scotsman was observing (8)
US celebrity cancelling finale to include European art form (5)
I haven't cracked this one yet — but Fifteensquared have:
( OPRA H [Winfrey {born 1954}], US celebrity excluding (cancelling] the last letter [finale] H ) containing (including) E (European)
Moved quickly - discovered with time to spare (5)
I haven't cracked this one yet — but Fifteensquared have:
T RACED (found; discovered) excluding (to spare) T (time)
Irregular soldier’s skill adopted by Italian city resident (8)
Irreverent about former monarch and very resistant to change? (10)
I haven't cracked this one yet — but Fifteensquared have:
IMPIOUS (irreverent) containing ( ER [Elizabeth Regina, former Queen of England] + V [very])
Very good book about Newton - though I wouldn’t think it would do for you! (4)
I haven't cracked this one yet — but Fifteensquared have:
( SO [very good] containing [about]) N [newton; derived SI unit of force]) + B (book)
Understand husband will give up son in plot (5)
I haven't cracked this one yet — but Fifteensquared have:
( GRA S P [understand] + H [husband]) excluding (will give up) S (son)
Chemical secretion increasingly reflected in dial (9)
I haven't cracked this one yet — but Fifteensquared have:
MORE (increasingly) reversed (reflected) and contained in (in) PHONE (dial a number, although nowadays you are more likely to press numbered buttons than dial)
Sailors tucking into meat about the time things are developing (6)
Meal excellent with additional helping of one ingredient (6)
I haven't cracked this one yet — but Fifteensquared have:
SUPER (excellent) containing an extra P ( with additional helping of one ingredient [letter]) to form SUP ( P ) ER
Down
I am turning up amongst a people not using English language (7)
I haven't cracked this one yet — but Fifteensquared have:
( I AM ) reversed (turning up; down entry) contained in (amongst) ( A + RAC E [people] excluding [not using] E [English])
French are imprisoning the old observers (4)
A few remain unsettled at heart in English county (8)
I haven't cracked this one yet — but Fifteensquared have:
SOME (a few) + R E S T (remain) with the two middle letters (at heart]) swapped round (unsettled) to form R S E T
No good blocking state payment for computer security item (6)
Vessel associated with a tower? (9)
One group of soldiers abandoning French city base (7)
I haven't cracked this one yet — but Fifteensquared have:
I (Roman numeral for one) + G RE NOBLE (French city) excluding (abandoning) RE (Royal Engineers, group of soldiers)
Hurrying to arrest fool? It’s very sad (11)
Supporting environmental targets subject to law about pollution (11)
Hide porn when getting treatment with new brain chemical (9)
Endless inducement to imprison fascist leader is a healthy sign (8)
Mad American‘s signal to bring in unruly pack (7)
Range around US city looking up inducing fainting fit (7)
I haven't cracked this one yet — but Fifteensquared have:
SCOPE (range) containing (around) NY (New York; US city) reversed (looking up; down entry)
Get rid of power in fuel with some energy extracted (6)
I haven't cracked this one yet — but Fifteensquared have:
P (power) contained in (in) DI E SEL (fuel] excluding [extracted] the first [one of] E [energy])
Decoration though denied second top award in pageantry (4)
I haven't cracked this one yet — but Fifteensquared have:
POMP OM (decoration) excluding (denied) the second occurrence of [second] OM (Order of Merit; a top award)
Type letters or click words in the clue