caucatc
Another relevant factor in UK airspace is that the SMF [a computerised separation monitor] does not know the difference between a visual separation and a loss of Radar separation. If we lose 5 miles/1000 feet, or whatever separation is required in a particular piece of sky...it can be more in some London ACC airspace, it will flag up on the supervisor's desk; instant suspension results. Even after a positive pass of opposite direction flights, re-inforced by both pilots' visual confirmation, climb/descent is forbidden until the required Radar separation is achieved.