The North Korean ship was spotted with another unknown vessel (Picture: Crown Copyright).
The Royal Navy has caught tankers smuggling fuel to North Korea, in what the United Nations (UN) has described as significant violations of sanctions imposed on the country.
HMS Montrose has collected evidence of North Korean vessels attempting to get around fuel restrictions placed upon them, following nuclear and ballistic missile tests in 2017.
The North Korean-flagged tanker SAEBYOL, which was transmitting as a fishing boat, was spotted alongside a vessel of unknown nationality on the high seas, conducting a prohibited ship-to-ship transfer.
Defence Secretary Gavin Williamson said: "Our Royal Navy presence in East Asia over the last year has been a robust deterrent against those trying to evade international sanctions on North Korea.
"Sanctions evasion helps facilitate North Korea’s nuclear weapons programme and is a major source of funding.
"Sanctions will remain in place.
"The Royal Navy will keep enforcing them until we see concrete steps towards North Korea’s complete, verifiable and irreversible denuclearisation."
Commander Conor O’Neill, the Commanding Officer of HMS Montrose, said: "Our work here in East Asia is just part of what the Royal Navy does all over the globe on operations which ultimately help keep Britain safe.
"I am proud of my ship’s company for their hard work gathering evidence of this illegal activity.
"This is a complex process but we were more than up to the task."
HMS Montrose is the fourth vessel to take part in enforcing sanctions against North Korea since the start of last year, after HMS Sutherland, HMS Albion and HMS Argyll deployed in 2018.