Britain remains bold (5)
I believe the answer is:
brash
'bold' is the definition.
(I've seen this before)
'britain remains' is the wordplay.
'britain' becomes 'br' (abbreviation).
'remains' becomes 'ash' (I've seen this before).
'br'+'ash'='BRASH'
(Other definitions for brash that I've seen before include "Unable to hear" , "Tasteless in appearance" , "Audacious" , "Crudely showy; bumptious" , "Flashy, crude" .)