Ex-president requires hand with task to perform (10)
I believe the answer is:
mitterrand
'ex-president' is the definition.
(I've seen this before)
'hand with task to perform' is the wordplay.
'hand' becomes 'mitt' (synonyms).
'with' is a charade indicator (letters next to each other).
'task to perform' becomes 'errand' (an errand is a task or job).
'mitt'+'errand'='MITTERRAND'
'requires' acts as a link.
(Other definitions for mitterrand that I've seen before include "President" , "Old statesman" , "Ex-President" , "Foreign statesman" .)