The incident came days after Royal Marine Commandos intercepted a Russian shadow fleet tanker carrying sanctioned oil in the Channel on Sunday, in the first operation of its kind carried out by the British military.
A Nato source told BBC Verify the Admiral Grigorovich had been ordered by Moscow to escort “shadow fleet” vessels through the Channel.
Following Russia’s full-scale invasion of Ukraine in 2022, the UK and its G7 allies imposed unprecedented sanctions on the Russian energy sector, including an Oil Price Cap.
Russia has been operating a “shadow fleet” to evade these sanctions.
Responsible for carrying 75% of Russia’s sanctioned oil, the fleet of more than 700 vessels provides a critical lifeline for the Kremlin, the MoD said.
Askins said a warship might also sail in international waters as a “geopolitical signal” to show they can operate there.
“I think nations will always bend their warship into areas and through passages just to demonstrate that there is a freedom of navigation,” he said.
Askins added that this kind of behaviour is common globally.
“It’s a bit like when the Russians send their aeroplanes over and they fly as close as they can and they work out when our RAF jets finally get to them and intercept them – so there’s always that little bit of probing,” he said.
“It’s not just our country… there are trainings in Greece and Turkey. Countries do that kind of [thing] all the time.”
In May, BBC Verify analysis suggested that almost 200 Russian shadow fleet vessels have entered UK waters since the prime minister threatened to intercept them nearly seven weeks prior.
In March, Sir Keir Starmer announced that British armed forces “are now able to board sanctioned vessels that are passing through our waters”.
