Each of twelve clues contains a misprinted letter in the definition part. Corrections of misprints spell a four-word phrase forming an indication of the unclued lights in each of four columns in the grid. Ignore an accent in one unclued light.

Across

1    Tremulous nut faced by snake (5)
4    Photograph taker’s last joke among whimsical exercises (9)
10    Barriers left a dog so bemused (10)
11    Crazy, revolutionary country music (6)
12    Poet nasty to saint (7)
14    Leaf lay beside railroad (5)
15    Trustee with diamonds in haul (5)
16    Brother, genuine playwright (6)
22    Raw information put over in learned English (8)
23    Taxis caught by us in great square (7)
24    Hesitation, stumped at first (4)
25    House with additional part leans (4)
27    Locks spring back, broken by pressure with spike (7)
29    Set awry, see, mostly constricted (8)
32    Old scoundrel penning note concerning vision (6)
34    Mapped lake enclosed by clan (5)
35    Irregularities in British borders (5)
36    Oceanic wind returned, disrupting film (7)
37    Opacity in article left enthusiast with nothing (6)
38    Strong urge to take in new cat (10)
39    Impudence against seer involved jest (9)
40    Clubs in affair on screen (5)

Down
1    Mathematician troubled tribal sage (10)
3    Throw earth on road round about (6)
5    One in awkward spot hired for journalistic position (10)
7    Alien in craft raised fist (5)
9    Slave seen struggling (4)
13    Tries trousers, right away (7)
15    Idiots ending in argument over asparagus, upset (6)
17    Salute rich, complicated philosopher (10)
18    Calamitously corpulent colleague (7)
19    Count stopped by hunter, endlessly critical (10)
21    Carry away amateur exhibit (6)
30    Fret over support lacking a series of names (6)
31    Flesh pots initially restricted by island (5)
34    Plant species at home (4)

A first prize of £30 for the first correct solution opened on 20 June. There are two runners-up prizes of £20. (UK solvers can choose to receive the latest edition of the Chambers dictionary instead of cash — ring the word ‘dictionary’.) Entries to: Crossword 2263, The Spectator, 22 Old Queen Street, London SW1H 9HP. Please allow six weeks for prize delivery.