Green’s Dictionary of Slang

slab-dabber n.

[journalistic jargon slab, a lengthy paragraph + SE dab (down)]

a left-wing hack journalist.

[UK] ‘’Arry on [...] the Glorious Twelfth’ in Punch 30 Aug. 97/2: Champagne lunches and gillies? That’s not what these slab-dabbers hate. It’s ‘Priviliged Classes’, my pippin, they loathes.