If Europe was at war, who would be called up first and how would they be trained to fight?

When news broke this week of Russian drones encroaching on Polish airspace, it was not only Warsaw and Brussels that jolted to attention. Across Europe, and here in the UK, the grim question has once again surfaced: how prepared would we be, really, if the unthinkable happened and a major war broke out on our continent? Nato chiefs have been blunt, warning that civilians must be ready to play their part. And that raises a sobering thought: if war came, would we actually have the manpower for battle? Who would fight, and how quickly could civilians become soldiers?

This question may sound abstract in Britain in 2025. We have become used to thinking of our armed forces as a lean, professional volunteer body – a far cry from the days of mass mobilisation. Yet events in Poland, and Nato’s warnings about civilian preparedness, remind us that conflicts in Europe can escalate with terrifying speed. If deterrence failed, Britain would be faced with the reality of having to field far more troops than our current army of just over 70,000 regular full-time personnel could muster.

I have seen with my own eyes how civilians can, with the right training, be turned into credible fighting men. The Ministry of Defence (MoD) has been leading Operation Interflex, a multinational training programme for Ukrainian soldiers, since 2022. Initially a basic combat course for civilians, it has evolved into a seven-week programme with advanced leadership and instructor training, tailored to the needs of the Ukrainian armed forces.

Last year, on a bleak training ground in southern England, I watched a squad of six young Ukrainians approach a dummy house. They moved silently, almost like dancers, flowing into positions they had drilled over and over. Within a minute, the “house” was cleared. This was no Hollywood shoot-’em-up. It was urban warfare training – cold, efficient, and absolutely real in its purpose.

These men were not career soldiers. Only weeks earlier, they had been IT technicians, digger drivers, postmen or students, about to enter into a programme that would transform them from civilians into fighters. On arrival, they were issued with 65 items of kit, shown their bunks, and plunged into 35 days of relentless instruction: weapons handling, trench warfare, battlefield first aid, mine clearance, urban combat. What takes between 12 and 18 weeks for a British recruit is condensed into little more than a month.

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The effect is profound. As Lieutenant Colonel Wilson, who commands the Interflex Training Delivery Unit, told me: “They come out walking taller and prouder. We do the basics really well, and we’ve been doing this for a really long time.” A senior Ukrainian officer put it even more bluntly: “Our best recruits come from Interflex.”

I met Vlad, a 23-year-old IT technician who would soon be on the front line. He was tall, slim, handsome, and already carrying that thousand-yard stare soldiers often acquire after combat. He told me quietly that he had lost friends, but still volunteered because he had to defend his homeland. Then there was Vitalii, 25, a burly digger driver. He admitted the course was tough, but knew he would be better prepared because of it. Both young men were conscious that in just a few weeks they might be fighting – and dying – in Ukraine’s trenches. I have no idea today whether they are still alive.

That civilian-to-soldier pipeline is exactly what several European countries have institutionalised. Finland obliges nearly all young men to serve in the armed forces, with alternatives for conscientious objectors. Sweden, rattled by Russia’s aggression, reintroduced conscription in 2017. Poland, now directly threatened, has invested heavily in territorial defence forces and civilian training, and has sent 40,000 troops to be deployed on its eastern border as it prepares for Russia and Belarus’s huge spectacle of joint military drills, called Zapad 2025.

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These European military schemes are not a nostalgic throwback but a pragmatic insurance policy: a way to ensure that if the balloon goes up, thousands already know how to fight.

Britain, by contrast, abandoned compulsory service in 1960. Back then, young men were called up for two years, with exemptions for certain professions and deferments for students. The system was often unfair – those with connections dodged more easily – but it created a vast pool of men with basic military training. Were we to contemplate something similar today, the debate would be about not just logistics, but fairness and consent.

In the Second World War, unmarried men aged 18 to 41 were the first to be drafted, with “reserved occupations” such as miners, doctors and clergy exempted. Women were conscripted, too, though typically for war work rather than combat.

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In today’s Britain, any call-up would look very different. Gender neutrality would be essential, as Norway already demonstrates. Doctors, paramedics, cyber specialists, and energy workers might be kept out of combat but still obliged to serve. The key would be fairness: nothing corrodes morale faster than a sense that the privileged can buy their way out.

Sceptics argue that drones, AI and long-range missiles have rendered mass armies obsolete. Ukraine shows otherwise. Drones can spot the enemy, AI can crunch targeting data – but only human beings can clear a trench, hold a street, or sweep a house. That is why Ukraine keeps training civilians by the thousand. It is why Finland and Sweden maintain their drafts, and why Poland has shifted to a war-footing posture. Numbers matter. Without sufficient manpower, even the most sophisticated weapons are hollow assets.

If, heaven forbid, Britain were drawn into a major European war, how would we prepare? A plausible option is a selective form of national service: short, intense training cycles – perhaps six to nine months, or even a five-week Interflex-style model – creating a pool of reservists who could be recalled. A dual track would widen the net, with civilians trained for hospitals, logistics, cyber defence and emergency response as well as combat.

General Sir Patrick Sanders, the former Chief of the General Staff, has been clear. He warned that Britain must prepare for a “whole-of-nation undertaking” and that “Ukraine brutally illustrates that regular armies start wars; citizen armies win them”. His argument was not for blanket conscription, but for the foundations of a voluntary call-up if needed. That idea may be unpalatable, but it is becoming increasingly difficult to dismiss.

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We should not be naive. Training civilians into soldiers is possible – I have seen it happen in five weeks – but it comes with costs. Lives are disrupted, studies postponed, careers derailed. Some are simply not suited for combat, and pushing them into it risks psychological damage. Politically, too, governments must be honest. This is not a rite of passage. It is preparation for horror. It is justified only by the gravest of threats, and only if administered fairly.

When I watched those young Ukrainians moving silently through a mock house in southern England, I realised how fine the line is between peace and mobilisation. One month, you are an IT technician or working on a building site; the next, you are clearing buildings and preparing for the possibility of death.

The events in Poland this week have reminded us that Europe is not immune to war. For Britain, the question is not only whether our jets can fly or our submarines sail, but whether we have the people ready – and if not, how quickly we would be able to train them. Interflex shows it can be done. The Ukrainians have proved it. The uncomfortable question is whether, if war did come, we would be willing to do the same.