This morning I was riding to work and decided to skip through traffic that was built up at a roundabout. The road leading into the roundabout is a single lane each way. The only way to cut through on the left side of the cars is to own an off-road bike, which I don't. So my only two options were to sit in traffic like a cage, or cut on the right side of the cars, meaning I would either be on the white lines or on the wrong side of the road. I was cautious in my approach and only moved forward when there was no oncoming traffic, there was plenty of time to see vehicles and react accordingly. As I start to ride past the traffic, a cop car decides to appear in the oncoming traffic. I pull back into the lane as I would have if it was any car and was just waiting to see the lights flashing as there is no chance they didn't notice me riding ON THE WRONG SIDE OF THE ROAD! But nothing, not even a nod of dis-approval as they went past. If they were watching in their rear-view mirror they would have seen me back on the wrong side of the road again. Now if I was just filtering or even splitting between two lanes going in the same direction I could understand them not caring or even noticing, but I was on the wrong side of the road. I'm not complaining that I didn't get a fine, just expressing my surprise. Has this happened to anyone? And is this still considered filtering or just overtaking?