When DW’s Zhanna Nemtsova asked what evidence the British parliament has to support this judgment, Johnson replied: "The reason I said what I did was because if you look at the stuff that's been used, it is a Novichok agent according to our scientists. You also have to consider that Sergei Skripal, the guy that they attempted to assassinate, is somebody who has been identified as a target for a liquidation and that Vladimir Putin has himself said that traitors, i.e. defectors such as Mr. Skripal, should be poisoned. So it's a Russian-only nerve agent."

Johnson justifies his direct accusation against Russian president Putin of having ordered the assassination. "You know he's in charge of the clattering train as we say in the UK. Somebody has to be responsible, somebody has to be accountable and we in the UK think that the evidence for culpability points to the Russian state. As it did in the case of Alexander Litvinenko and you remember the trail of polonium led back very clearly to the Russian state. And in the end Mr. Putin is in charge and I'm afraid he cannot escape responsibility and culpability." 

While Boris Johnson might favor a constructive cooperation with Russia on the issue, this could be difficult to achieve after his direct allegation against president Putin.

"We said: 'Look this stuff is Novichok. If there is a rational explanation of how it has escaped your stockpiles and how it has come to be used on the streets of Salisbury then come on let's work together and get to the bottom of it. If, on the other hand, there's no explanation, we can only conclude it's the agency of the Russian state and we got no answer.'"

The Kremlin has told London that they would like to review the case materials. Johnson seems reluctant about granting access to Russian investigators. 

“The first is that I think we will trust the technical experts of the Organization for the Prohibition of Chemical Weapons who are arriving in the UK. Let's see what their assessment is. That's the proper procedure that the UK has to follow under the Chemical Weapons Treaty. I find the Russian position about what has happened to this Novichok absolutely bizarre, increasingly bizarre. And, of course, if the Putin regime can clarify or explain what has happened, then we are all ears and we are only too willing to listen.”

The British government has so far denied Russian diplomats access to Yulia Skripal, who is a Russian national. Johnson puts this decision into context. 

“I hesitate to sound protective of that. Let me just say that to the best of our knowledge agents of the Russian state have just tried to assassinate both Yulia Skripal and her father. So I think it's our job at present to try to protect them as far as we can.” 

The British foreign secretary is confident of the support by the EU and the USA, which might possibly include measures like sanctions to be taken by other nations in solidarity with the UK.

“The objective is not to punish the people of Russia at all. The objective is to try to show that we care deeply about the kind of disruptive and dangerous and reckless behavior, reckless with human life that we've seen from Russia and that we want to put pressure on the regime. To find a new path and there can be calls for hope. But there won't be calls for hope if we simply allow this kind of thing to happen.”