Joe Byrne

"Our analysis and previous reporting indicates a significant portion of the oil shipped to North Korea in circumvention of sanctions has come out of Taiwan ports over the past years," said Joseph Byrne, a research fellow at the Royal United Services Institute.

Over in London, Joseph Byrne, a North Korea expert at the defence think tank the Royal United Services Institute (RUSI), was equally stunned. "I never thought I would see North Korean ballistic missiles being used to kill people on European soil," he said. He and his team at RUSI have been tracking the shipment of North Korean weapons to Russia ever since Mr Kim met his Russian counterpart Vladimir Putin in Russia in September of last year to strike a suspected arms deal.

Given that neither Russia nor North Korea has admitted to arms transfers, there is no way of knowing exactly how significant their contribution is to Russia's wider supply of munitions for the war. But "the volume of stuff that's been going over is huge. It's significant," Joseph Byrne, an open-source researcher and North Korea specialist at the Royal United Services Institute, told BI.