Across
A look maintained by Starmer, with British sangfroid (6)
I haven't cracked this one yet — but Fifteensquared have:
A (directly from surface); plus LO (look [over there!]) inside PM (Prime Minister [Keir] Starmer); plus B (British)
Best ever performance from leftist full of goodness (6)
Son remains in Cambridge University to succeed (5,2)
I haven't cracked this one yet — but Fifteensquared have:
S (Son); plus ASH in MIT ASH=”remains” after burning or cremation MIT=University in Cambridge, Massachusetts
Computer file appended to mail for researcher (7)
Dope and beer left in building for event involving parties (7,8)
I haven't cracked this one yet — but Fifteensquared have:
GEN=information/knowledge=”Dope”; plus ALE=”beer” + L=”left”, both inside ERECTION=”building”
See 18
Government naturally welcomes learner drivers here (4,6)
Discouraging inaccurate activity on 13 (3-7)
12a
Check revenue, gutted by tax (8)
Hammered pale worker’s failed balancing act (9,6)
I haven't cracked this one yet — but Fifteensquared have:
TIGHT=drunk=”Hammered”, plus anagram/”failed” of (pale worker)*
Articles from Germany and the UK, say, about craze (7)
I haven't cracked this one yet — but Fifteensquared have:
DER=definite ‘article’ in German + AN=indefinite ‘article’ in English; plus E.G.=for example=”say” reversed/”about”
Double whiskey brought in to Jacob’s dwelling? (7)
I haven't cracked this one yet — but Fifteensquared have:
W (whiskey, NATO alphabet), inside both of: TO (from surface) + FOLD=”Jacob’s dwelling” edited thanks to Valentine in the comments a FOLD is an enclosure for sheep, and a Jacob is a type of sheep
Farage is hanging around charming companion (6)
Helen’s lover speaking drunkenly in priest’s district (6)
I haven't cracked this one yet — but Fifteensquared have:
PARISH might be a drunken pronunciation of ‘Paris’ Paris=”Helen’s lover” in the myth of the Trojan War
Down
Actor in a suit with no pattern turning up fine suit (9)
I haven't cracked this one yet — but Fifteensquared have:
definition: “Actor” and “suit” as in starting legal action PLAIN=”with no pattern”, plus reversal of: F (fine) + FIT=”[to] suit”
Parents mustn’t have married different people (6)
I haven't cracked this one yet — but Fifteensquared have:
[m]-OTHERS=”Parents”, minus m for “married”
During binge, sober stars pusillanimously withdraw (6,3)
I haven't cracked this one yet — but Fifteensquared have:
BOUT=”binge”, around: TT (teetotal, “sober”) + LEO=constellation of “stars”
Drive back from Carlisle, perhaps heading north (5)
Singer Johnny Rotten’s no. 1 covered by one of The Police – a cultivated product (4,4)
I haven't cracked this one yet — but Fifteensquared have:
CASH=(Singer Johnny Cash) + first letter (no. 1) of R-[otten] inside COP=”one of The Police”
Bones possibly set, with a different bit at the end? (5)
I haven't cracked this one yet — but Fifteensquared have:
definition: plural of radius, a bone in the arm RADI-[O]=”possibly set”, with I instead of O at the end I and O referred to as different ‘bits’ of digital information – 1s and 0s
TV magnate with fraudulent investing scoffed, given a sweetener (5-6)
I haven't cracked this one yet — but Fifteensquared have:
SUGAR (Alan Sugar [wiki] , “TV magnate”), plus COD=sham=”fraudulent” around/investing ATE=”scoffed”
Presumed crook judge ticked off loses head (11)
Better to keep good list in a part of the index? (9)
I haven't cracked this one yet — but Fifteensquared have:
definition: part of the index finger FINER=”Better” around G (“good”); plus TIP=to tilt or lean=”list”
Queen upset king breaks often shaky, special bonds (4,5)
I haven't cracked this one yet — but Fifteensquared have:
ER (Elizabeth Regina, “Queen”) reversed/”upset”; plus K (king) inside anagram/”shaky” of (often)*; plus S (special)
Regularly shout ‘cheats’ where politicians speechify (8)
I haven't cracked this one yet — but Fifteensquared have:
regular letters from [s]-H-[o]-U-[t]; plus STINGS=deceives=”cheats”
Figure holding Virginia up is Grace’s partner (6)
I haven't cracked this one yet — but Fifteensquared have:
definition refers to the phrase ‘grace-and-favour’ [wiki] FOUR=numerical “Figure”, around VA (Virginia, US state) reversed “up”
Current prince deprived of electronic stuff (5)
I haven't cracked this one yet — but Fifteensquared have:
G-[e]-ORGE=Prince George of Wales=”Current prince”, with e for “electronic” removed”
Endless test about case of police work at the Met (5)
I haven't cracked this one yet — but Fifteensquared have:
definition refers to the Metropolitan Opera [wiki] ORA-[L]=”Endless test”, around the outer letters (“case”) of P-[olic]-E
Type letters or click words in the clue