A British warship shadowed a Russian frigate through the English Channel on Tuesday, taking over monitoring from French surveillance on the frigate's voyage northwards.
HMS Argyll, a navy ship maintained at high-readiness, deployed a Lynx helicopter and used sensors to locate and monitor the Russian warship Yaroslav Mudryy, which was en route to the North Sea from the Mediterranean.
"Under the NATO agreement whereby alliance nations co-operate to monitor activity, the Royal Navy took over from French surveillance," Britain's Ministry of Defense said in a statement.
A ministry spokesman estimated that a Russian warship was escorted through the Channel every few months.
In a more unusual incident, Britain last month summoned the Russian ambassador after two Russian Bear long-range bombers flew over the Channel, disrupting civil aviation and prompting Britain to scramble two Typhoon fighter jets.
Relations between Russia and the West have soured in recent months over Moscow's perceived role in the conflict in eastern Ukraine and its annexation of Crimea. Many other European countries have reported what are widely seen as displays of Russian military prowess.