A large number of Russian warships have been active in British waters last Monday. The British have raised the alarm at all NATO allies because of the Russian threat.
Ships of the Russian navy have appeared more often in the waters of European countries in recent years. In March, August and November of this year, the British already saw a number of warships in their part of the sea. This involved, for example, seven or nine ships. That was also the reason that the British sounded the alarm in NATO.
The English Channel is an international strait, free for peaceful and lawful traffic
That doesn’t mean that the Royal Navy is not free to shadow naval vessels passing through, if they so desire. (As long as they don’t interfere with safety and freedom of navigation)
PS> NATO ships shadowing Russian (Soviet) fleets and Russians shadowing NATO exercises is nothing new and will probably continue as long as the animosity between the two continue.