GP: How has Vladimir Putin responded to Ukraine's push into these territories that he has just annexed? And in his view, are they part of Russia? "The Russian response was, we are not firm and clear about where the borders of the annex territories are" GP: The further Ukraine pushes into these annexed regions, the more likely Putin is to use nuclear weapons. Whether he will or not is, I mean, nobody knows. It's a risk you have to take it seriously, but nobody seems to think it's likely."