The alarm sounded just after 1pm on 12 May at Ämari Air Base, where the Royal Air Force is stationed to deter Russian aggression in the Baltic states.

This article was originally published on 20 May 2016.

Nine hundred miles away, inside a control room in the German city of Uedem, staff at NATO’s Combined Air Operations Centre were tracking three unidentified aircraft.

The aircraft had not filed flight plans, and two were not “squawking” identification codes – both breaches of international flight procedures.

The RAF’s 140 Expeditionary Air Wing arrived in Estonia in early May with more than 140 personnel and four Eurofighter Typhoons to provide Baltic Air Policing on NATO’s behalf. Just an hour earlier, they had taken part in a flypast over Estonia’s main towns to send a clear message that NATO was there to protect the Baltic states – and now they would have to prove it.

Typhoon aircraft lifting off from the Ämari Air Base. Photo: UK Ministry of Defence

Within minutes of the alarm, two RAF Typhoons were taxiing to the edge of the runway as Estonia’s air traffic controllers made urgent attempts to establish radio contact with the unidentified aircraft.

The pilots knew they might face a long wait on the runway, as they are often asked to sit “at slingshot”, engines running, while suspicious activity is monitored.

But not today.

Air traffic controllers managed to establish radio contact with only one aircraft, while the other two flew in radio silence amid commercial traffic through Estonia’s flight information region.

NATO command gave the order to intercept, and the RAF Typhoons roared down the runway on their first operational task since arriving. Seconds after take-off, they banked sharply left, flying north-west over Estonia’s forests before pursuing the unidentified aircraft above the Baltic Sea.

Typhoon aircraft arrival at the Amari Air Base in Estonia as the prepare to start a period of Baltic Air Policing. Photo: UK Ministry of Defence

Within minutes of take-off, the RAF Typhoons pulled up on the left-hand side of each aircraft in turn, close enough to peer into the cockpits. The unidentified planes were now identified as an AN-26, an AN-12 and an IL-76 – known to NATO as a Curl, a Cub and a Candid. All were Russian military transport aircraft.

Once the identification was complete, the aircraft were judged to pose no immediate threat, and the RAF pilots were ordered to shadow them instead. The only shots fired came from the digital cameras issued to RAF crews to document intercepts.

The RAF Typhoons dropped a mile behind the Russian convoy, and together they headed west past Estonia before turning south to follow the Baltic coastline.

As the convoy approached the flight information region of the Russian enclave of Kaliningrad, the RAF peeled away and returned to base in Estonia, completing what one pilot described as “textbook intercepts”.

A collective NATO responsibility

The UK defence secretary, Michael Fallon, denounced the incident as “an act of Russian aggression”, adding that the RAF’s instant response demonstrated Britain’s commitment to NATO’s collective defence.

The incident reflects a pattern of behaviour not seen since the height of the Cold War, with Russian aircraft – including fighter jets and bombers – refusing to “squawk and talk” while flying close to NATO airspace and testing weaknesses in response times.

The Russian government disputes this, insisting that all its flights comply with international norms.

Maintaining airspace integrity is a collective NATO responsibility, with the alliance committed to providing the same level of protection for all members. The Baltic states of Estonia, Latvia and Lithuania are too small to sustain a quick-response capability on their own, so other member states’ air forces provide Baltic Air Policing on four-month rotations.

The Baltic states have been NATO members since 2004, but the need to scramble jets in response to Russian aircraft only escalated a decade later, after Russia’s 2014 invasion of Ukraine and the subsequent deterioration in relations with the West.

The RAF Typhoons used for Baltic Air Policing were developed under the Eurofighter programme, launched in 1984 to produce an agile combat aircraft capable of chasing and outmanoeuvring Russian fighters over central Europe. They entered service in 2003, by which time they were widely criticised as outdated Cold War relics, ill-suited to a world where the Russian threat was thought to have receded.

That irony is not lost on Wing Commander Gordon Melville, who leads the RAF’s 140 Expeditionary Air Wing at Ämari.

RAF Wing Commander Gordon Melville at the Ämari Air Base in Estonia. Photo: UK Ministry of Defence

The day after the intercept, Melville sits in an office overlooking the runway as routine flights take off once more. This time, the aircraft bank sharply right after departure to join NATO forces in Exercise Spring Storm, held in south-eastern Estonia near the Russian border.

The RAF Typhoons are taking part in both simulated ground-attack and air-defence missions during the annual exercise, which involves more than 6,000 troops from Estonia, the UK and other allies. For Estonian soldiers it serves as a final exam, while the US Department of Defense has described it as a chance to reassure the region of NATO’s resolve.

“The Typhoons are exceptional and can stay airborne for quite some time,” Melville says. “Everything is measured in minutes to get to the extremities of all airspace in the Baltic region so a pilot could be asleep in bed and then alongside a Russian aircraft less than 15 minutes later.”

“We work very well with all our NATO colleagues to provide 24/7 uninterrupted protection of Baltic airspace. We’ve got Russia to the east and the Russian enclave of Kalingrad on the other side of the Baltic states so there are a lot of flights taking place, but not all of them follow the correct procedures.

“There’s always lots of chatter and if anything is bubbling up then our guys will start to prepare. If something looks suspicious then we can bring them to several stages of readiness, including having them ‘at slingshot’ with the engines running at the edge of the runway.”

As Melville speaks, radios around the room buzz with a mix of accents. British pilots, engineers and support staff make up the largest contingent on base, but Ämari is also home to Americans, Poles and Dutch personnel alongside their Estonian hosts.

Remarkably, the air base was originally built by the Soviets during their occupation of Estonia in the Cold War, and once housed Sukhoi SU-24 aircraft.

Ämari lies south-west of Tallinn, reached by a forest road that passes a cemetery where some former Soviet residents are buried beneath gravestones fashioned from aircraft tail fins. Soviet-era stone buildings still dot the base, but they stand empty and dilapidated in stark contrast to the modern facilities built since NATO began using it in 2014.

Russia has repeatedly branded any development or renovation at Ämari a provocation, yet further expansion of the base’s infrastructure is already under way by the US Air Force.

Typhoon aircraft arrival at the Ämari Air Base in Estonia. Photo: UK Ministry of Defence

“The facilities here are state-of-the-art,” Melville explains. “Our Estonian hosts and other NATO colleagues are all really helpful and we all work as one team to ensure we can conduct our mission successfully. We are all pooling our capabilities together and that is really the genuine power of the NATO alliance.”

Quick reaction

The scramble siren is heard across the base, ensuring all personnel – whether directly involved or not – know a mission is under way. The real hub of activity, however, is the Q-Shed, short for Quick Reaction.

Pilots enter the building for 24 hours at a time, while engineers remain for a full week. The only reason any of them leave is to intercept aircraft – everything else, from meals to new books, is brought in. Inside the Q-Shed, the food is distinctly British, with the RAF flying in its own catering from the UK to provide a sense of home and familiarity.

During this period, everything the pilots and engineers do – including eating and sleeping – takes place in their flight gear, just metres from at least two fully fuelled and armed aircraft. The pilots even sleep in their boots, wearing both a G-suit for high-speed manoeuvres and an immersion suit in case they end up in the Baltic Sea that night. Anything else they need is carefully laid out between their beds and the cockpit, where the helmet is the final item they put on.

A UK fighter pilot posing with his Typhoon fighter. Photo: UK Ministry of Defence

“The entire building has been designed and set up to get aircraft into the sky as fast as possible,” one of the pilots says. “We have automated our processes as much as possible so when the alarm sounds the entire place will light up and the hangar doors start opening. The pilots will usually have no idea what the mission is until they are airborne.”

“Every second counts,” Melville adds. “It is not normal to be sound asleep then airborne within minutes, but we monitor fatigue very carefully and there are lots of strict rules in place to make sure that the risks are at the absolute lowest.”

The Typhoons can reach speeds of more than 1,700 km/h (1,056 mph) within two minutes if NATO Command orders the Baltic Air Police to go supersonic, though this is usually avoided because of the sonic boom that would rattle homes below.

The RAF was scrambled again on Tuesday for its second operational task in less than a week, after five aircraft were detected flying through Estonia’s flight information region. None were squawking recognised identification codes or communicating with air traffic control.

The RAF intercepted the aircraft within minutes and this time identified four Russian fighter jets and a reconnaissance plane, which were escorted to Kaliningrad’s flight information region.

Kaliningrad has become a focal point of rising tensions in the Baltic region as Moscow continues to militarise the enclave. The most serious incident came in April, when the USS Donald Cook, sailing 70 nautical miles off Kaliningrad, was buzzed by two Russian Su-24s that staged a simulated attack, making multiple passes as low as 30 feet above the ship.

The US deputy defence secretary, Bob Work, condemned the incident as reckless and unnecessary, adding that the Russian military was becoming increasingly aggressive in both the Black Sea and the Baltic.

“We came out last year for Baltic Air Policing and responded on 17 occasions to 40 aircraft, including 10 aircraft in one go,” Melville says. “This mission is really important for the UK and NATO. It’s all about reassurance and we need to have that protection over the Baltic states, just as we do over the UK and other NATO skies.

“Several years’ experience operating in this area indicates that we can expect further similar activity in the months ahead,” Melville adds. “Our mission continues, and our NATO allies can stand assured of the UK’s full support for their defence.”