Passed directly underneath it yesterday approaching LND. We were 6000' below it but London ATC gave us the heads up and we saw it approching from the south as we headed west. The contrails appeared to be much bigger than anything else we pass and there was a very noticeable roll-over of the contrails in the wake vortex. It was probably on the way to Iqualit. Sadly, camera battery was duff and so couldn't get a picture.