ATC don't separate traffic in the circuit, usually.
Which ATC would that be? Elsewhere, on a recent trip I asked for, and was given, a wrong-way base join, but as I couldn't see the aircraft on the right-way base join and they couldn't see me I was given an orbit by ATC (fair enough, I could have avoided this by asking for an overhead join). By the time I'd finished the orbit the othe aircraft was over the fence and I was given a land-after; that sounds like separation to me.