During the Cold War, British tanks never went east of Berlin. But in November, soldiers from the U.K.’s 3rd Armored Division were in Poland, training for high-tech combat against a powerful foe such as Russia.

How times have changed. Or not changed at all.

More than 2,000 troops from the United Kingdom and Poland—including 20 Challenger 2 and 56 Leopard 2 tanks—linked up for the Black Eagle exercise near Żagań, in western Poland, from Nov. 3 to Nov. 21.

“The exercise will test responsiveness, interoperability enhancement, and provide demanding opportunities to conduct small to medium sized armour and mechanized infantry field training,” NATO’s Supreme Headquarters Allied Powers Europe announced as the training kicked off.

The practice sessions allowed British forces to test how fast they could rush into a major battle against a determined enemy—again, Russia comes to mind—and whether their Polish compatriots could be ready for them when they got there.

Like other NATO militaries, the British Army has spent the last decade fighting insurgents in Iraq and Afghanistan. Large tank battles were far from planners’ minds—and rarely factored into anyone’s training.

British Army engineers get a tank ready for the exercise (Crown Copyright)

Four years ago, NATO’s Allied Rapid Reaction Corps, which is ready to spring into action at a moment’s notice, moved from Germany to the U.K. But like its American allies, the British Army still keeps vehicles in storage on the continent for exercises like Black Eagle—and for more serious operations.

For Black Eagle, engineers arrived early to head up an “Activation Task Force” to make sure the Challengers, Warrior fighting vehicles and other equipment were good to go. But some of the tanks had served in Iraq and were in need of repairs and upgrades, according to an official news story on the war game.

The Challenger 2 is Britain’s only tank. It totes a 120-millimeter gun and boasts layers of so-called “Chobham armor.” The armor—found only on Challengers and American M-1 Abrams tanks—is a classified mix of ceramic plates, metal reinforcements and other materials.

London sent approximately 100 armored vehicles to the Żagań Karliki training area for Black Eagle. And Warsaw’s own armor was ready to meet them.

After more than a decade, Poland is still a relatively new NATO member. But the former Warsaw Pact nation readily sends troops to fight overseas and is pouring money into its armed forces.

Black Eagle gave Poland’s 10th Armored Brigade a chance to show its mettle. The unit operates the country’s fleet of modern Leopard 2 tanks.

The German-built Leopards are among the best tanks in the world and also possess a 120-millimeter gun and thick armor. Last year, Poland announced it would be buying dozens more of the 60-ton vehicles.

British Army Challenger 2 tanks at Black Eagle (Crown Copyright)

Despite taking place hundreds of miles from Poland’s eastern frontier, Black Eagle’s training sessions served as a warning to Russia. London and Warsaw are both concerned by the fighting between Ukrainian forces and Russian-backed separatists.

At the end of March, Moscow seized control of Ukraine’s strategic Crimea region after the pro-Russian government in Kiev collapsed amid mass protests. In the months that followed, a bloody insurgency exploded in parts of eastern Ukraine. Russia has sent in troops and has also supplied the separatists with heavy weaponry.

While the conflict has now devolved in a stalemate, some NATO countries—especially Poland and the Baltic States—worry bloodshed could jump their borders.

“[Black Eagle] clearly demonstrates our focused resolve … supporting assurance measures and in defending the Alliance and its territory,” said Belgian lieutenant colonel Marcus Nieswand, a NATO planner. The Alliance has held a large number of war games this year in response to Russia’s intervention in Ukraine.

British soldiers are scheduled to stay in Poland into the middle of December. And the two nations could organize additional exercises in coming months.

“Exercise Black Eagle shows that the NATO alliance is alive and well,” British Army chief of general staff Gen. Sir Nick Carter told reporters.