Oil supertanker from Russian port docks in Southampton

ExxonMobil says cargo came from Kazakhstan

A supertanker that sailed from Russia has docked at a port in Southampton with a cargo of crude oil for ExxonMobil.

The Seatribute is one of at least 148 tankers carrying oil and gas that have left Russian ports since the war in Ukraine began, according to shipping data gathered by Greenpeace.

The data recorded by MarineTraffic reveals that 69 tankers sailing from Russia are due to dock in European ports.

Another two tankers coming from Russian fossil fuel terminals, the CB Caribic and the Baltic Mariner, are due to arrive in the UK in coming weeks.

Grant Shapps, the transport secretary, asked port authorities to ban Russian ships in late February as part of a break with financial ties with Moscow in response to the invasion.

The government estimates around 10 tankers have been turned away so far.

The ban only covers vessels owned or operated in Russia or by Russians, leaving a loophole whereby Russian cargo delivered by ships registered elsewhere can be unloaded in the UK.

The Seatribute is registered in Malta but sailed from Novorrossiysk in Russia to land at Fawley dock on Friday afternoon.

The Baltic Mariner is also registered Malta while the CB Caribic is registered in Spain.

ExxonMobil, which has a refinery in Fawley, said the oil was from Kazakhstan but was transported through Russia via the Caspian pipeline.

The ExxonMobil Esso Oil refinery in Fawley, near Southampton (AFP/Getty)

The pipeline primarily moves product from Kazakh oil fields but around 10 per cent of its oil comes from Russia, according to figures from the Caspian Pipeline Consortium.

The arrival of Russian gas has encountered strong opposition from workers in the UK.

Last week, two tankers were diverted away from the Isle of Grain in Kent by dockers.

Shell this week was forced to apologise over its decision to purchase a cargo of Russian crude at a discounted price, and the company has now pledged to stop buying oil from the country.

The Unison trade union, representing dockers, said there was “confusion” over the ship sanctions and called on the government to close the cargo loophole.

The UK currently relies on Russia for 4 per cent of its gas imports and per cent of oil imports. The government this week pledged to phase out Russian oil and reduce demand from Russian gas by two-thirds by the end of the year.