DW: How close were we to a casus belli earlier this week when an American drone crashed into the Black Sea after an encounter with two Russian planes in international airspace?

Lord George Robertson: I think we've got to be very worried about incidents that can take place that might lead to escalation. I'm not sure whether this particular incident falls into that category — we need to know much more about it — but I think it's being handled reasonably soberly at the present moment.

But, you know, the Russians — in the whole of what they're doing just now — are being as provocative as possible. The invasion of Ukraine was one of the biggest provocations we have seen in the last 30 years, so we can probably expect more provocations in the future and we need to be ready to face them.

Former Ukrainian Prime Minister Yulia Tymoshenko has suggested that Eastern Europeans were not taken seriously when they drew attention to the danger posed by Russia.

When Putin came to power, we thought we had a partner in many of the challenges we faced. Russia faced the challenges of terrorism, of climate change, of population movements. So, many of the threats were common threats, and it looked as though Vladimir Putin had a common view about the security at the time.

I think that was genuine, but gradually, over time, he's changed his view, become much more paranoid, much more demanding, much more buried in some concept of Russian history. But I don't think that we can assume that we're dealing with the Putin of yesterday today. The one today is a major challenge to all of us and we have to face that challenge.

Russian propaganda says that Russia was provoked.

Russian propaganda is based on total dishonesty. Vladimir Putin seems to claim that Gorbachev was tricked on NATO enlargement. He seems to claim that [former President Boris] Yeltsin was tricked into signing the Budapest Memorandum and the Helsinki Accords.

What I know is that in May 2002, Vladimir Putin himself signed the Rome Declaration along with me and 19 other signatories, which protected the territorial integrity of all states. And specifically that day he guaranteed the territorial integrity of Ukraine. So the Russian propaganda is based on lies. And the sooner these lies are exposed to the Russians, the better it will be.

Romania is a member of NATO; Moldova is not. What should Romania do if Russia were to step up its aggression against Moldova?

Well, that's a hypothetical situation. I've got a great deal of affection for Moldova, which I visited on several occasions. I know how vulnerable they are at the present moment. And I hope that the world will keep its attention focused on Moldova, and that the Russians will keep their hands off it.

How likely is it that Ukraine will be admitted to NATO?

Well, that will be a decision taken by the heads of state and government at some future NATO summit. And if Ukraine satisfies the criteria in terms of military compatibility and democratic credentials and good neighborly relations, then the decision will be taken on a political basis by the summit meeting at that time. I'm long away from NATO. I've got no finger in that pie. That'll be for a future summit meeting to make a decision on.

Edited by: Aingeal Flanagan