[Repost comment for visibility] There was debris on the Wellington straight, before Vettel went off.

I posted this comment in the Vettel tyre video, but that was hours ago, and my comment got buried, but I think you'll all be interested in what I said:-

It's possible. There was debris on Wellington straight, just after the bridge. I'm not sure what it was from, or if it was sharp. Source: I was the marshal operating the lights at that location, and turned the change-of-surface light on at that location because something shattered and spread across the track.

Look again at the in-car footage. You'll see change-of-surface displayed on the light board on the right hand side just before the bridge (I was operating that one). Just after the bridge, you'll also see the flag marshal displaying a change of surface flag, on the right hand side just after the bridge - that was also where I was stood - if you freeze-frame the picture about 10 yards after the flag point, you can see something on the circuit. It's blurry, but there was definitely something there. There were a lot of small pieces, but they got cleared/picked up pretty quickly as cars ran over it.

I'm still not sure what the debris was or what it came off, and a lot of it was collected by cars as they went through it.

edit: Having said all that, the debris didn't look like it had anything big/sharp in it, but weakened tyres could have suffered a small cut just enough to tip the balance. It could of course all be a coincidence, and the debris had nothing to do with it.

My comment with context
Link to video - in car replay I refer to is approx half way through.