I flew Denver to Heathrow on a BA B777 on the morning of the 25th February. The moving map on the inflight tv (dunno how accurate that is) was showing a tailwind of 179 mph at one point. It was quite bumpy and the cabin crew had to strap in for a while until the driver eased it a bit further north of track and into a more sedate 85 mph tailwind. A lot of severe weather over the Eastern US at that time.
Flight time was reduced from a normal 9 hours to 8 hours! I imagine that flying westwards would have been very slow progress.