Green’s Dictionary of Slang

(W.I. Rasta) a preferred term for SE oppressor.

1980		M. Thelwell Harder They Come 208: Through [...] the schemes of the down-pressors of the righteous, there had had to be a change in the evening’s ceremonies.
1981		N. Farki Countryman Karl Black 12: Death to all down-pressors. De...a...th to those who trod upon the children of Africa.