Spike took a sip from his mug of nicely warmed, nicely human blood, and eyed the Master cautiously. "Hadn't put two and two together, actually, but if you're that one and that's your Jack... Yeah. That Ianto's quite a nutter, i'nt he?"
That being Spike's not-so-subtle way of trying to divert the Master's attention to Ianto rather than Jack.