Coming in to work today and doing the usual thing of filtering as you do. There was a point where I had to stop at a set of red lights and when it turned green, I shot off, with all the other bikes in tow. This is one of those areas where the speed drops from 80kph to 60kph and occasionally there's Plod waiting for the unsuspecting bikes. So I slowed down to 80ish and two bikes overtook me. The traffic built up again, so it was automatic filter mode, with the other two bikes in front of me. By this time, the two bikes in front must have been about 100m away. I saw a cage move from the left lane to the right from standstill, as they do. Typical cage manoeuver where the other lane is moving 2kph faster than their lane. However, the lead bike was going to fast (IMO) and didn't have time to stop. I saw the brake lights come on and the bike shoot off to the right of the cage. My first thought, was, 'I don't think he made that.' Y'know, the manoeuver where you give the bike a flick to get round an obstacle that encroaches on your path. Sure enough, I arrived at the scene and saw the damage. The biker was already on his feet on the pavement. No real damage to him, but a sore leg and possibly sore wrist. The bike had side swiped the cage crunching the passenger door (and smashing the window and ripping off the mirror) and somehow had been projected into the cage in front, smashing the rear window. (Didn't see any other damage to the cage in front besides that). Glass all over the place. Damage to the 600 Divvy was more cosmetic. Broken indicator and damaged bikini fairing, with crunched and dented exhaust. I couldn't see any frame damage (well, anything obvious). The biker in front of me had stopped too and another numpty biker, that seemed to have lost the power of speech, as he didn't speak for the whole episode. The cage driver admitted that he didn't see the biker in his mirror and my thoughts were, 'Why the fuck didn't you do the lifesaver?' Plod and Pompiers were called, as the law says that if there are injured parties to an accident, they should be called. Even if the injuries are slight. Not a lot I could do really. I checked over the injured party, made sure he was okay, etc, etc and left my details with him. (Does anyone leave their details with a cage driver, in the event of a bike/cage collision?). My parting words were, 'Well, I know it hasn't started that way, but try to have a good day anyway.' But the way it is, the biker was at fault. Filtering too fast through traffic. Let's be careful out there folks. HAND.