To wafu, I think we're talking REAL on-call here, as opposed to going to the NAAFI bar and getting rat-arsed every night. It means staying sober and sitting at home.
I get 11 hours OT per month plus a minimum of 4 hours OT per call.
That works out as £0.77 per hour for my social life (for what it's worth) being screwed.
Deep joy