Ukraine’s government has urged the UK to ensure “not a single drop of Russian oil enters the country”, as it pushed for a “total and immediate” boycott on Russian fossil fuels.
Oleg Ustenko, economic adviser to President Volodymyr Zelenskyy, said it was “no time for half measures”. It comes amid concerns Britain may adopt a definition of Russian oil that allows some Kremlin supplies into the country, even under the impending embargo.
The UK Government is banning Russian oil imports to try and limit inadvertently aiding Putin’s war effort, giving UK buyers until the end of the year to adapt before the policy comes into force.
However Whitehall says it is still working with industry to “develop a clear definition of what constitutes Russian oil,” raising concerns that products containing some molecules from the country’s produce might still be allowed through.
Diesel and other refined oil products can contain a mix of supplies from several countries under long-standing industry practice or because they have been stored in mixed tanks.
There are also concerns that oil from Russia is increasingly being mixed with supplies from other countries to obscure its origin, as traders try to keep energy supplies flowing while avoiding criticism for aiding the Kremlin.
In a statement to the Telegraph, Mr Ustenko said: "We would welcome the UK engaging with Ukraine on how they define Russian oil - after all it's our people being killed with the proceeds.
"For us, every drop of Russian oil is Blood Oil. For the UK to really stand alongside Ukrainians, we need to see a total - and immediate - boycott on Russian fossil fuels.
“Russia will always seek to find loopholes in whatever sanctions and policies the UK puts in place. This is no time for half-measures.
“The only way to avoid customers in Britain inadvertently helping Putin is to ensure not a single drop of Russian oil enters the country or is traded by UK-based companies."
Shell, one of the world’s largest oil and gas companies, has pledged to withdraw from Russian oil products, but defines refined versions, such as diesel, as not being of Russian origin if less than 50pc of the blend is from the country.
The UK typically gets about 8pc of its oil from Moscow, almost all in the form of refined products diesel and jet fuel. Disruption to diesel markets amid the war has forced up UK diesel prices to an average 176.11p as of Sunday.
While Britain’s embargo is impending, the EU is still debating whether to ban Russian oil imports amid concerns over the impact on its own economy. Both the UK and the EU have also not yet banned imports of natural gas from Russia.