No Deal act, Boris and I worked up - it helped Johnson win once (8,7)
I believe the answer is:
anabolic steroid
'it helped johnson win once' is the definition.
The definition suggests a singular noun which matches the answer.
'no deal act boris and i worked up' is the wordplay.
'and' is a charade indicator (letters next to each other).
'worked up' is an anagram indicator.
'no'+'deal'+'act'+'boris'+'i'='nodealactborisi'
'nodealactborisi' anagrammed gives 'ANABOLIC STEROID'.
Can you help me to learn more?
(Other definitions for anabolic steroid that I've seen before include "in the event it's banned" , "this may provide therapeutic treatment" , "performance enhancer" .)