In mid-February 2022, Ukraine's border guard agency intercepted a piece of evidence that should have been decisive. A commander of a Chechen unit stationed in Belarus reported to Ramzan Kadyrov, the Kremlin-installed leader of Chechnya, that his men were in place and would soon be in Kyiv.

According to The Guardian's investigation, as reported by "Hvylya", the recording was shown to President Zelensky. But it failed to convince him, a well-informed source said.

At security council meetings, the prevailing view remained unchanged: a full-scale invasion was unlikely, and the military buildup was about applying economic and political pressure on Ukraine.

"Lots of us were uneasy, but I guess everyone decided that the safest thing was to agree with the president," said one senior Ukrainian official.

The intercept was yet another ignored signal in a series of warnings that had been coming to Kyiv since November 2021 - from the CIA, MI6, and personally from CIA Director William Burns. All of them broke against Zelensky's conviction: Russia operated in the grey zone of hybrid warfare and would never dare launch open aggression. The scale of Russian losses in the war that followed has exceeded all projections, while Ukraine has invested heavily in innovative defense technologies to counter the threat.