The day I left London was a bit damp which made for a bit of vapor on departure.  I was sitting almost directly over the wing.  I couldn’t see in to the inlet but I could see vapor puffs in front of the inlet at lower speeds anyway.  As we rotated and climbed out, there was plenty of vapor puffing over the upper surface, aided by climbing through a few patches of cloud.  I had the video running the get a view of the moisture and here is what I got.