I've played with the little switch on the scart lead, from RGB to AV and back again to no avail, I've also tried playing with a few settings on my TV. (This is all UK PAL (i presume) equipment).
The ps2 doesn't flicker on his TV, and neither does my TV flicker when i play videos from a VCR (via scart), movies from my computer (via s-video) or normal TV (from the aerial in socket), so why is the ps2 flickering like a motherfuck?