11 across
One
secures
Milligan
no
trouble
(5-4)
One secures Milligan no trouble (5-4)
-
hints
0
checks
0
hints
The definition is at the beginning of the clue.
How the clue works
One secures is the definition — a spike-nail is something that fastens. The wordplay is a charade: SPIKE (referring to comedian Spike Milligan) followed by N (abbreviation for 'no') and AIL (meaning 'trouble').