Rwanda has ill-prepared border protection (8,4)

I believe the answer is:

hadrian's wall

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'border protection' is the definition.
'hadrians wall' can be an answer for 'border' (I have seen 'Old border' mean 'hadrians wall' so perhaps 'border' could also mean 'hadrians wall'). I am not sure about the 'protection' bit.

'rwanda has ill-prepared' is the wordplay.
'prepared' indicates anagramming the letters.
'rwanda'+'has'+'ill'='rwandahasill'
'rwandahasill' with letters rearranged gives 'HADRIANS WALL'.

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I've seen this clue in The Sunday Times and The Times.

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