Influences outcomes at Britain, leading from the front (5)
I believe the answer is:
bends
'influences' is the definition.
(bend can mean to warp or influence)
'outcomes at britain leading from the front' is the wordplay.
'outcomes at' becomes 'ends' (I can't explain this - if you can you should give a lot more credence to this answer).
'britain' becomes 'B' (common abbreviation as in GB).
'leading from the front' is a charade indicator (letters next to each other) (some letters go in front of others).
'ends' put after 'b' is 'BENDS'.
Can you help me to learn more?
(Other definitions for bends that I've seen before include "deadly to the diver" , "Painful divers' condition" , "Buckles" , "Diver's affliction" , "Road curves" .)