In a candid assessment that could spark renewed debate within India’s defence and strategic community, Jack Watling, a leading land warfare expert at the Royal United Services Institute (RUSI), has urged New Delhi to urgently re-evaluate the combat resilience of the Russian-made S-400 air defence system. His remarks come against the backdrop of mounting evidence from the Ukraine conflict, where the system’s performance under sustained, high-intensity combat conditions has been called into question.
Speaking to The Hindu, Watling—who has advised Ukrainian forces and regularly briefs NATO militaries—stopped short of recommending that India abandon its existing S-400 contracts with Russia. Instead, he argued for a more sober, evidence-based reassessment of the system’s strengths and vulnerabilities, warning that battlefield realities in Ukraine have exposed shortcomings that glossy marketing claims can no longer obscure.
Watling acknowledged that the S-400 has delivered value to India in limited scenarios. He specifically cited its reported role during “Operation Sindoor,” launched in response to the 2025 Pahalgam terror attack, when the system was deployed to deter potential Pakistani aerial activity. According to available accounts, the S-400 helped impose caution on adversary air operations, reinforcing India’s air defence posture during a period of heightened tension.
However, Watling drew a clear distinction between such controlled, short-duration deployments and the demands of a prolonged, full-spectrum war. “While the S-400 has demonstrated an ability to engage high-value targets at long range, Ukraine shows what happens when such systems face sustained suppression campaigns,” he said.
In Ukraine, Russian S-400 battalions have operated in an environment saturated with decoys, loitering munitions, electronic warfare systems and persistent intelligence, surveillance and reconnaissance (ISR). Under these conditions, several batteries have reportedly suffered rapid attrition, losing key launchers and, crucially, their radar components. Once radars are destroyed or forced offline, even the most advanced interceptor missiles become ineffective.
According to Watling, the issue is less about flawed Russian engineering and more about a fundamental transformation in the character of warfare. The S-400 was designed primarily to counter traditional threats—manned aircraft, ballistic missiles and cruise missiles launched in limited numbers. Modern battlefields, by contrast, are increasingly dominated by swarms of cheap, expendable drones that can exhaust defences through sheer volume.
He pointed to specific episodes, including drone attacks in Crimea in late 2025, where S-400 batteries were reportedly overwhelmed by low-cost unmanned systems. “When a multi-million-dollar missile is used to shoot down a drone that costs a few thousand dollars, the defender is already losing the economic war,” Watling noted.
Compounding operational concerns are emerging questions about Russia’s defence-industrial capacity. Recent RUSI assessments and open-source intelligence suggest that production of advanced air defence radars depends heavily on foreign-sourced components. These reportedly include Western-origin microchips and beryllium oxide ceramics sourced from Kazakhstan—materials that are difficult to replace domestically at scale.
International sanctions and disrupted supply chains have raised doubts about Moscow’s ability to sustain, repair and upgrade complex systems like the S-400 over the long term. For existing operators such as India, this has implications not only for future deliveries, but also for spare parts, maintenance cycles and promised enhancements.
Watling cautioned India against taking Russian assurances of imminent “upgrades” at face value. While Moscow has spoken of improvements such as enhanced anti-jamming capabilities and faster system mobility, many of these measures remain in testing or early deployment stages. “There is a difference between a prototype fix and a proven solution that works under fire,” he said.
Nevertheless, the RUSI expert was careful to underline that he is not advocating a rupture in Indo-Russian defence ties. “I am not suggesting India tears up its contracts,” Watling clarified. “Russia remains a key partner, particularly because it has historically been more willing than others to transfer technology.”
Instead, he urged New Delhi to adopt a pragmatic, non-ideological approach to air defence planning. Central to this, he argued, is diversification. No single system—however advanced—can guarantee airspace security on its own.
Watling recommended that India accelerate efforts to build a layered air defence architecture. In such a model, the long-range engagement capabilities of the S-400 would be complemented by highly mobile, shorter-range systems specifically designed to counter drones, loitering munitions and low-flying cruise missiles. Integration with electronic warfare, passive sensors and rapid-repair logistics would be equally critical.
The warning, Watling stressed, is not unique to India. It applies to all nations modernising their militaries in an era of rapid technological change. The central lesson from Ukraine is stark: assumptions that held true a decade ago can collapse quickly under the pressure of modern combat.
As the war in Eastern Europe continues to rewrite the rules of air and missile defence in real time, Watling argued, the only viable path to security lies in constant adaptation—testing systems not against brochures and simulations, but against the unforgiving evidence of the battlefield.
