The Foreign Office summoned Moscow’s ambassador to London this afternoon to complain about a flight by two Russian bombers over the Channel, which Britain says posed a potential danger to civilian flights.

The Ministry of Defence confirmed that RAF Typhoon jets were scrambled to intercept a pair of Tupolev 95 “Bear” planes on Wednesday, as they flew along the south coast. A spokeswoman said: “The Russian planes were escorted by the RAF until they were out of the UK area of interest. At no time did the Russian military aircraft cross into UK sovereign airspace.”

A FCO spokeswoman said: “While the Russian planes did not enter sovereign UK airspace and were escorted by RAF Typhoons throughout the time they were in the UK area of interest, the Russian planes caused disruption to civil aviation. That is why we summoned the Russian ambassador to account for the incident.”

There have been several Russian military flights close to UK airspace in recent months, causing British fighter jets to be scrambled.

It is unusual but not unknown for such flights to come along the south coast, over the channel, but a British official said: “This time they caused more disruption and concern than before when we have had to send Typhoons up to take a look. So that’s why we called the ambassador in.” The Russian ambassador, Alexander Yakovenko, came to the FCO at 4pm.

Flights by Russian planes close to British and other Nato members’ air space have become more frequent as tensions have increased between Moscow and the west, particularly over the war in Ukraine. Last month, the Swedish government complained that a Russian military aircraft had been flying near its airspace with its transponders turned off to avoid being spotted by civilian radar, and nearly collided with a passenger jet.

British officials said they could not confirm whether transponders were turned off on the planes flying close to the English coast on Wednesday. “Disrupting civil aviation is one thing. Having a strategic bomber close to your airspace is another,” a Nato official said. “If they have their transponders turned on, then civilian aviation can see where they are and what they are. If they are off, that’s when we have to get up there to find out.”

“We have had to fly four times more intercepts in 2014 than in 2013. That’s 400 times. Either they don’t follow a flight plan or they file it and we get up there and it’s a different kind of aircraft flying. It doesn’t help when they turn off the transponders. All Nato planes on all missions have their transponders turned on.”

Observers said a possible explanation of the timing ofWednesday’s flypast was the start this week of a public inquiry in London into the 2006 killing of a former Russian intelligence officer, Alexander Litvinenko, by radioactive poisoning.

The UK has charged two former KGB agents with the murder. A lawyer for Litvinenko’s widow has claimed in court that the assassination was ordered by Vladimir Putin.

“This may be timed with the Litvinenko court case as a signal of displeasure,” Ian Kearns, the director of the European Leadership Network, and an associate fellow at the Royal United Services Institute, said. “But it fits with a wider posture of a more assertive Russian demonstration of a growing capability to defend and assert its interests as it sees fit.”