ACROSS

1  Change my code for a laugh (6)
4  Accomplished (8)
9  Murderous Gale (6)
10 … but everywhere in chains? (4, 4)
12 Joanna, jewel-thief in 3, 15 (9)
13 Determined airman from Peril at End House (5)
14 Queen tours SA all over but ends up in London NW1 (6,6)
18 What Adam did – by firing a pistol? (5,3,4)
21 Number of Acts in a Tragedy (5)
22 Bring out each year – like a Christie for Christmas? (9)
24 __ Lane, third victim at Hickory Road (8)
25 Franciscan spiritual home still is as is? (6)
26 His horses were a Herculean labour (8)
27 Rain in Chipping Cleghorn obscures Miss Marple’s favoured form of transport (2,4)

DOWN

1. Gas container (8)
2 “Elle sera ___ – et si vous me mettez en colère, je la ferai Duchesse!” Molière, Le Bourgeois Gentilhomme (8)
3,15 O, he hated Linnet! And this was the result (5,2,3,4)
5  Kate Bush song for which the video was directed by Terry Gilliam, starring Donald Sutherland (11)
6 “I will arise and go now, and go to ____ ” (WB Yeats) (9)
7  Hedley, cricketer and Nemesis victim (6)
8  Spanish governess (6)
11 Party (12)
15 see 3
16 Location of Miss Springer’s murder in Cat Among the Pigeons (8)
17 Blake mithered about one of the little pigs? (8)
19 “Oh dear, I have been incredibly ___” – a typical Miss Marple self-deprecation (6)
20 Cave (6)
23 Cleric lose his head – it’s a crime (5)