A Canadian submarine was on the front lines as NATO allies scrambled last fall to track a “surge” of Russian subs that had deployed into the North Atlantic, the Star has learned.

HMCS Windsor, already in European waters for a NATO exercise, was re-tasked on a mission to try to track the Russian vessels.

Rear-Adm. John Newton, commander of Maritime Forces Atlantic, called the movement of Russian submarines “historically significant.”

“There was a quite a surge of Russian strategic power . . . it was moving a lot of boats around the North Atlantic,” he told the Star this week.

On the move were five Russian attack submarines, a show of force that might have been Moscow’s response to “Trident Juncture,” NATO’s largest exercise in a decade, involving 36,000 personnel from more than 30 nations.

But with the Russian boats active, the exercise turned real as NATO nations responded with ships and aircraft.

That included the HMCS Windsor, one of four Victoria-class submarines operated by the Royal Canadian Navy, which had been taking part in the NATO drill.