The Admiral Grigorovich, a Black Sea fleet frigate, accompanied a pair of shadow fleet ships on Wednesday while a British naval vessel followed behind.

Positioned on the Royal Charlotte, a boat almost 10 miles from Dover, the Telegraph observed Putin’s flotilla cruising past the south coast while RFA Tideforce, a Royal Fleet Auxiliary tanker, trailed in their wake.

Last month, Sir Keir gave special forces the authority to capture the armada of rusted ships illegally ferrying oil to support Russia’s war in Ukraine, saying he would hit the shadow fleet “even harder” if they sailed through British waters. However, Britain is yet to seize a single Russian vessel.

The Prime Minister has repeatedly faced criticism regarding the state of the Royal Navy and Britain’s Armed Forces. After an Iranian-made drone hit RAF Akrotiri, HMS Dragon, Britain’s only deployable destroyer, was sent to the Middle East, but took three weeks to arrive and has already had to return to port as it suffers water supply issues.

In a speech on Saturday, Kemi Badenoch, the Conservative leader, is expected to pile further pressure on Sir Keir, urging him to publish the long-delayed defence investment plan. She will state that there is “no plan for rearming Britain”.

Donald Trump, the US President, has previously described the Navy’s two aircraft carriers as “toys” while his War Secretary, Pete Hegseth, mocked Britain’s “big, bad Royal Navy”.

The US first stormed a Russian sanctioned oil tanker in January, prompting pledges from Western nations to seize more ships.

While the French navy has intercepted some tankers in the Mediterranean, dozens of Russian vessels are believed to have passed through the Channel since Sir Keir’s threat.

Admiral Grigorovich – a 3,620-ton frigate armed with anti-ship, cruise and surface-to-air missiles – sailed between the two 600ft tankers Universal and Enigma shortly after 9am on Wednesday as they headed west toward Plymouth.

Universal reportedly departed from the Russian port of Vysotsk on January 18th.

The Russian-flagged tanker is believed to be on a mission to deliver crude oil to bolster the Kremlin’s coffers, which are straining to fund Putin’s war machine.

In September, she was outlawed in British waters for attempting to “destabilise Ukraine or undermine or threaten” Kyiv by exporting oil from Russia to fund its invasion.

Meanwhile, the Cameroon-flagged Enigma was bound for Turkey, having left port at Primorsk, north of St Petersburg, on March 29th. She was sanctioned by the UK in May last year for pumping money to the Kremlin.

On Wednesday, the Telegraph identified two other sanctioned Russian tankers – the Gambia-flagged Desert Kite and the Kousai from Sierra Leone – sailing through the Channel in the opposite direction, having entered on Tuesday evening.

Andrew Fox, a retired major in the Parachute Regiment, said the Russians were seeking to humiliate Britain.