RAF Typhoon fighter aircraft were scrambled from RAF Lossiemouth today to monitor two Russian planes approaching UK airspace.
The Ministry of Defence confirmed Russian Blackjacks long-range bombers were not talking to air traffic control.
A statement said the lack of communication from the Russian planes made them a hazard to all other aviation.
The Ministry of Defence said the jets were monitored by the RAF and Nato partners as they passed through international airspace before they were intercepted by the RAF over the North Sea.
“Subsequently, our fighters escorted the Russian Blackjacks north, out of the UK’s area of interest,” a statement said.
“At no time did the Russian bombers enter UK sovereign airspace.”
Defence secretary Gavin Williamson said: “Russian bombers probing UK airspace is another reminder of the very serious military challenge that Russia poses us today.
“We will not hesitate to continually defend our skies from acts of aggression.
“Once again the rapid reactions of our RAF have demonstrated how vital our Armed Forces are in protecting Britain.”