The laid down procedure for a missed approach from a circling approach, is a climbing turn into the overhead to re-establish onto the missed approach procedure for the instrument approach segment. (PANS-OPS 8168). As from a straight in procedure resulting in a missed approach, commence with the instrument approach go-around until obtaining clearance to re-establish in the visual circuit. I saw an aircraft do a go-around from an unstabilised approach and position itself onto a visual downwind resulting in a direct conflict with an aircraft already established on the downwind leg!