NVIDIA will not undercut AMD and they also will not price it under 970, the 1060 shall go in the gap the 980 once was with similar performance at around 300 quid because that gives NVIDIA a good lineup as 970 and 960 shall remain for a few more months which fill the 220GBP and 150GBP gaps.
There's no way people will buy a 1060 for £300.
It doesn't have the prestige of the x70 or x80 cards, let alone the Ti or Titan.
It's a 5th tier card - people will not pay £300.
Likewise, nobody is going to pay £250 for an x50 nVidia product.
They're going to get a reality shock if they release at this price. Who do they think they are, Apple?