1: Went ahead and used the power button (7,2)
2: Ill-conceived encore run for Edward VIII, say (9)
3: Bobbed beneath in playful attempt to drown journalist. (6, 5)
4: Martyr fighting segregation (5,6)
5: Clear initial rubbish in drain (3)
6: Hold onto string and file (5)
7: Messages transmitted about a mile (1-4)
11: Quite put out, doctor axes red tape (11)
12: Criticise a computer analysis of famous passage (6,5)
15: Harvesters of needlefish eating there (9)
16: Crooner Mel: famous, loveless, suffering (9)
19: Result of incident (5)
20: One side of the page a clergyman does not finish (5)
23: Height is equal to three-fifths of the first one (3)