Clue: Trickster's gossip in support of British ruler (4,6)
Answer: BRER RABBIT
Explanation: Trickster's gossip in support of British ruler (4,6)
A charade of BR ('British') plus ER ('ruler') plus RABBIT ('gossip'; more often the sense is "talk inconsequentially", but as the derivation seems to be rhyming slang RABBIT and pork – talk – so 'gossip' would seem to be an acceptable definition). 'In support of' gives the order of the particles in a down light.