A Russian spy ship has been tracking British-led military exercises in the Baltic Sea, the Task Group commander has revealed.

The Fodor Golovin has been monitoring Britain’s “full-fat warfighting capability” in the Baltic Sea, in the largest Royal Navy deployment to the area in a century.

Over 4,000 troops, including 1,100 Royal Marines, and 44 ships from seven countries have conducted wargames over recent weeks.

The British-led Joint Expeditionary Force (JEF), a new nine-nation defence organisation, has been deployed in the area since May, close to the sensitive Russian enclave of Kaliningrad. The deployment will end in July.

Speaking exclusively to the Telegraph from Lithuania, on board HMS Albion, the Royal Navy’s flagship, Commodore James Parkin, the Commander of the UK Amphibious Task Group, said: “We expected to see Russians having a look at this new organisation and they’ve come out and had a look at us. And we’ve looked at them looking at us.

“If I was going to expect a reaction, or more people being interested in us, it’s going to happen in the next few weeks. That’s what we’re looking out for and expecting and we welcome that as a sign of our ability to operate with friends”.