Europe starts learning how to shoot down drones

In public European officials say they are not certain who has sent these drones.

IT SOUNDS LIKE the opening of a Tom Clancy novel. Late on December 4th five drones appeared above the Île Longue naval base in Brittany, which houses France’s nuclear-armed submarines. Their appearance was sufficiently alarming to prompt marines to target the aircraft with jammers. They were not the only intruders in European airspace. Days earlier multiple drones flew to a spot at Dublin airport that would have been in the flight path of the plane carrying Volodymyr Zelensky, Ukraine’s president, had it not arrived early.

An explosion of a drone lights up the sky over Kyiv during a Russian attack on Saturday.

In public European officials say they are not certain who has sent these drones. In private they acknowledge that Russia is likely to be behind many of the incidents. The sighting in Dublin, noted the country’s prime minister, was “suggestive of being part of an ongoing Russian-inspired hybrid campaign”. It followed other sightings over military bases and critical infrastructure in northern Europe in the autumn, prompting Denmark’s defence minister to point to a “hybrid attack”. French officials suspect that an oil tanker from Russia’s shadow fleet which French soldiers boarded in the Baltic sea in September may have been used to launch such drones.

The scale of the problem is hard to gauge. A huge number of commercial and hobbyist drones now criss-cross European skies. Britain estimates that there could be 76,000 commercial drones in its airspace by 2030. There were more than 3,800 close encounters between drones and planes over European cities in 2024, up from around 1,700 encounters the previous year, according to one study.

A genuine sighting can often lead to scores of spurious ones, as people become oversensitised. An investigation by Dronewatch and Trouw, two Dutch news outfits, found that in 40 of the autumn sightings there was little evidence of drones at all; in another 14 cases the actual phenomena turned out to be anything from stars to ships. But at least some of the sightings are likely to be hostile activity. An investigation by a group of German journalism students found that at least 19 drone sightings near the Dutch and German coastline were correlated with the movement of three Russian-crewed ships.

The first problem is detection. Traditional radars are calibrated to see large, fast-moving objects and to filter out smaller, slower-moving clutter, such as birds—or similarly sized quadcopters. The cheap solution is passive sensors that can scan radio traffic to detect when data is being passed between a drone and its operator. The pricier option is active radar, but that requires more people to set up and operate, and more effort to ensure that the radio emissions don’t disrupt nearby equipment.

The next problem is what to do about a stray drone. The first resort, as in France, is often a soft-kill technique, such as jamming, which cuts off a drone from the pilot, or spoofing, in which the drone is led to believe it is somewhere else. Increasingly, police protecting political leaders and public events can be seen carrying jammers, which resemble comically large guns. If jamming on standard frequencies fails, notes Justin Bronk, an expert at RUSI, a think-tank in London, then probably “they’re not using commercial-standard components, which makes it much more likely that you’re dealing with a state actor.”

Yet not every state actor uses advanced kit. Russian intelligence services have conducted much of their sabotage in Europe over the past year by paying criminal groups with cryptocurrency. That suggests even Russian-sponsored saboteurs might use commercial drones. Attribution has proved difficult. In November 2024 drones were reported above three Royal Air Force (RAF) bases used by America’s air force in Suffolk, Norfolk and Gloucestershire. More than 60 RAF personnel were sent to help. But even a year on, there is little evidence pointing to Russia.

If a drone cannot be coaxed down by electromagnetic means, the next step is a hard-kill option. The simplest is catching it in a net. The crudest is to fire guns at it. “A standard, unmodified infantry assault rifle is not a very good tool,” says Mr Bronk. The odds of hitting a drone with standard bullets, without specialist sights, are low. Shotguns are better, but even then specialised ammunition is needed. On November 22nd Dutch troops fired at drones over Volkel air base but found no wreckage, indicating that nothing was shot down. “These things can fly very, very fast and are very small, and can manoeuvre in six degrees of freedom in pretty unpredictable ways for a human,” says Mr Bronk. “It’s not like clay pigeon shooting.”

The equipment needed to detect and shoot down small drones is cheap compared with high-end air-defence systems. But it can require continuous monitoring. And because each system covers a small area, providing coverage to every plausible target in the country can become expensive. Ireland expects to spend €19m ($22m) on counter-drone systems, with a single battery deployed to Bandonnel airbase in Dublin, where foreign dignitaries often arrive. It can also drag scarce kit away from military sites to civilian ones. When drones disrupted Britain’s Gatwick airport in 2018, the RAF had to step in. But the same kit was needed to protect troops and airfields abroad. Belatedly, civilian airports have begun investing in their own technology.

But using it is still another matter. Authorities are loth to shoot down drones unless they are confident that they pose a threat, according to people familiar with the decision-making. The suspect drones in Dublin came within 500 metres of an Irish warship, but its crew were not permitted to fire at it. A falling drone could fall on people, houses or vehicles. Bullets fired upwards can travel huge distances and kill people on the ground. And just as the vast majority of bird strikes cause no serious problems to planes, a drone collision would not necessarily be catastrophic, notes Mr Bronk.

Only in the autumn did Britain, Germany, Poland and Lithuania begin changing their laws to allow police and armed forces to shoot down threatening drones. At present, authorities tend to shut down airspace and halt flights rather than risk an accident. That approach, which makes it easy for a malicious actor to cause havoc, is like using “a sledge hammer to crack a peanut”, says one insider. It also makes European governments look helpless. If Russian saboteurs are responsible for some of the drone disruption, their job remains trivially simple.