How long Britain could really fight for if war broke out tomorrow

Russia’s full-scale war on Ukraine will soon enter its fifth year. Mysterious incidents of so-called “hybrid warfare” are mounting in Europe, increasing tensions. And in the UK, military chiefs have warned we must prepare for war if we want to avoid it. But if the unthinkable happened, and war with Russia broke out, could the UK fight for more than just a few weeks?

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“We are not planning to go to war with Europe. But if Europe wants to, and starts, we are ready right now.” So said Russian President Vladimir Putin on 2 December, accusing European countries of hindering US efforts to bring peace in Ukraine.

To be clear, it is extremely unlikely that the UK would ever find itself in a war with Russia on its own, unsupported by Nato allies.

But Putin’s words were an uncomfortable reminder that a war between Russia and Nato countries, including the UK, was not as remote as people hoped.

“Well that’s odd. I’ve got no signal on my phone.” “Me neither. I’m offline. What’s going on?” That scenario, hypothetically, is just one way we could know that a war with Russia had begun, or was about to. (I should add that there can also be other, perfectly benign, reasons for a loss of signal.)

That signal interruption could be followed by an inability to make bank payments for essentials like food and fuel.

Food distribution would be disrupted, electricity supplies compromised.

There are many ways of fighting a war, and not just the physically destructive wave of drones, bombs and missiles so tragically familiar to the citizens of Ukraine.

Our modern, tech-driven society is highly dependent on the network of undersea cables and pipelines that connect the UK to the rest of the world, carrying data, financial transactions and energy.

Covert activity by Russian spy vessels, such as the Yantar, is widely believed to have scoped out these cables for potential sabotage in a time of war, which is why the Royal Navy has recently invested in a fleet of underwater drones equipped with integrated sensors.

In a war, these hidden, unseen actions, combined with an almost inevitable attempt to “blind” Western satellites in space, would seriously hamper the UK’s ability to fight, as well as potentially wreaking havoc on civil society.

At a recent conference in London entitled Fighting the Long War, organised by the Royal United Services Institute (Rusi), a Whitehall think tank, military and political figures came together to discuss whether the UK’s current armed forces would be in a position to sustain a protracted conflict before they ran out of everything from troops, to ammunition to spare parts.

“There remains little evidence that the UK has a plan to fight a war lasting more than a few weeks,” argues Rusi’s Hamish Mundell. “Medical capacity is limited. Reserve regeneration pipelines are slow… The British plan for mass casualty outcomes appears to be based on not taking casualties.”

With classic British understatement, he says: “This could be considered an optimistic planning assumption.”

He adds that to fight a long war you need proper back-up. “It demands a second and even third echelon; personnel, platforms and logistics chains that can absorb losses and continue the fight. Yet this depth is notably absent from current British force design.”

“There are shortfalls in ammunition, artillery, vehicles, air defence, and people, with limited to no ability to regenerate units or casualties,” says Justin Crump, CEO of Sibylline, a private intelligence company.

Two of the biggest military lessons to come out of the Ukraine war are firstly, that drones are now integral to modern warfare, at every level, and secondly, that “mass”, or sheer volume of personnel and military hardware, matters.

Russia’s army is generally of a very low quality. Its soldiers are poorly equipped, poorly led and poorly fed. Their life expectancy in the deadly “drone zone” of eastern Ukraine is short.

UK Defence Intelligence estimates that since the start of the full-scale invasion in February 2022 Russia’s army has suffered more than 1.1 million casualties – that is killed, wounded, captured or missing.

Even conservative estimates put the number of Russians killed at 150,000. Ukraine has also suffered catastrophic casualties but numbers are hard to ascertain.

But Russia has been able to draw on such a massive pool of manpower that it has so far been able to replace its estimated 30,000 monthly battlefield casualties with fresh blood.

Russia’s economy has also been on a war footing for more than three years now: an economist has been placed in charge of the Defence Ministry, while its factories churn out ever more supplies of drones, missiles and artillery shells.

According to a recent report by the Kiel Institute for the World Economy, Russia has been producing each month around 150 tanks, 550 infantry fighting vehicles, 120 Lancet drones and more than 50 artillery pieces.

The UK, and most of its Western allies, are simply not anywhere near this point.

Analysts say it would take years for Western Europe’s factories to come close to matching Russia’s mass-production of weapons.

“The land war in Ukraine has shown beyond doubt that mass is absolutely vital for anybody that is going to face Russia on land,” says Keir Giles, a Russia expert at Chatham House think tank.

“And having deep reserves vastly greater in number than the standing regular armed forces has been shown to be essential.”

France and Germany have both recently moved to revive a system of voluntary military service for 18-year-olds.

The UK’s former Head of the Army, Gen Sir Patrick Sanders, suggested in 2024, the year he retired, that the UK should train what he called “a citizen army” to fight a land war in the future. The idea was shot down by No. 10.

“I think it’s a cultural thing within the UK,” says Ed Arnold, senior research fellow at Rusi.

“So if you look at the states that are now looking towards [military service] – like Sweden, Germany and France – they are states who culturally still have an institutional memory of when they had that system.

“We haven’t had national service since the 1960s and attempts to have that national conversation around it have pretty much backfired.”

“The reality is, our armed forces cannot survive on a diet of government spin, over-the-horizon spending commitments and hollow rhetoric,” Sir Ben Wallace, who was Defence Secretary in the Conservative government from 2019 to 2023, told the BBC.

Responding to this, a spokesperson for the current Labour Defence Secretary, John Healey, told me: “This characterisation is baseless.

“We increased defence spending by £5bn this year alone, signed 1,000 major contracts since the election and increased MOD spending with British businesses by 6% above inflation in the last year.”

He points to a new defence agreement with Norway, a £300m new investment in the Royal Navy’s laser weapon and a £9bn investment into armed forces housing, adding: “We’re a government investing in the transformation of our forces, investing in our British service personnel… to create jobs and growth in Britain’s communities.”

But this is not about party politics. It’s about whether UK defence has been under-funded for so long that it has now reached the point where the country is dangerously vulnerable in several areas, notably air defence.

There are also problems of timing and inefficiency.

Defence contracts often take years to come to fruition. Billions of pounds have been spent on Ajax, an overdue armoured vehicle project still beset with problems. Meanwhile, Nato officers have been warning Russia could be in a position to launch an attack on a Nato country within three to five years.

At the end of the Cold War (between Nato and the Soviet Union) in 1990, when I was a young infantry Captain in the Army Reserves, the UK was spending 4.1% of GDP on defence.

The following year it deployed over 45,000 troops to help evict Iraq President Saddam Hussein’s invading army from Kuwait in operation Desert Storm.

Today, with multiple pressures on the economy, the government is striving to meet a target of 2.5% of GDP by 2027, while Russia spends close to 7%.

On paper, the British Army numbers around 74,000 but Rusi’s Ed Arnold points out that once you subtract medically non-deployable soldiers, defence attaches around the world and others not part of formed units, then its actual deployable strength is only 54,000. That is less than the average number of casualties Russia takes in two months in Ukraine.

In the event of a war, says Justin Crump of Sibylline, on land the (British) Army would most likely be degraded – incapable of fighting effectively – within weeks, once committed, though he adds “much depends on the form of the conflict”.

Some commentators have suggested that the UK is already “at war” with Russia. They are referring to what is known as “hybrid” or “grey-zone” warfare, which includes events that are often deniable, such as cyber-attacks, disinformation and the alleged launching of drones close to airports and military bases in Nato countries.

But worrying as these are, they pale compared to the crisis that would be triggered by a Russian military attack on a Nato country, especially if it involved seizing territory and people being killed.

There are several potential flashpoints here, where Nato military chiefs fear that Putin, if he were allowed to achieve his aims in Ukraine, could eventually move on to seek new targets for aggression.

One potential target is the Suwalki Gap, a 60-mile (100km) stretch of border between Poland and Lithuania, both Nato countries. This is all that separates Russian ally Belarus from the Russian exclave of Kaliningrad on the Baltic coast.

Seizing that border and opening up a route along it would, in theory, give Moscow direct access to its strategic base on the Baltic.

The Baltic states themselves are other potential flashpoints. Estonia, Latvia and Lithuania were all once part of the Soviet Union and were ruled from Moscow.

They all voted for independence and have since joined Nato, but all have Russian-speaking minorities and hence there is a risk that Mr Putin could be tempted to send his troops across the border “to protect them from persecution”.

The eastern Estonian town of Narva, for example, is an obvious potential target here, as the majority of its population speak Russian and it sits just across the river from the giant Russian fortress of Ivangorod.

A UK battle group comprising some 900 British military personnel has been stationed in Estonia, about 80 miles west of Narva, since 2017.

In the event of war, the plan goes, it would be hurriedly reinforced to brigade strength of around 3,000 or more.

Another possible flashpoint is the Arctic archipelago of Svalbard, which is administered by Norway but where Moscow already has a toehold in the coal mining town of Barentsburg.

The UK may well be Putin’s enemy number one, having been one of Ukraine’s staunchest allies, and having pushed for more powerful weapons to be delivered to help its defence.

Hostile acts on UK soil that have been linked to President Putin include the murder with radioactive Polonium-210 of former KGB officer Alexander Litvinenko in London in 2006 – a public inquiry concluded that Putin “probably” approved his assassination – and the attempted murder of former Russian military intelligence officer turned MI6 agent Sergei Skripal in Salisbury in 2018, using the nerve agent, Novichok.

Dawn Sturgess, a mother-of-three, later died after she sprayed the Novichok, disguised as perfume, on her wrists. Putin was “morally responsible” for her death, an inquiry concluded last week.

Lord Anthony Hughes, the inquiry chair, said: “I have concluded that the operation to assassinate Sergei Skripal must have been authorised at the highest level, by President Putin.”

Russia, which has always denied involvement in the attacks and suggested more than 20 different possible explanations for Ms Sturgess’s death, described the report’s findings as “tasteless fairy tales”.

But the UK is also a core member of the Nato alliance. While questions are certainly raised in private over the reliability of the current US administration in the White House, it is hard to envisage the UK ever having to fight Russia on its own.

“A pure UK-Russia conflict is not likely and can be disregarded, practically,” says Mr Crump. “We would definitely fight with allies, although Russia would most likely only launch a conflict if it felt Nato would break.”

The wild card here is US President Donald Trump.

While the chairman of Nato’s Military Committee, Adm Cavo Dragone recently assured me that the US president was absolutely committed to defending the Nato alliance, others are not so sure.

Would Trump, for example, go to war to defend the Estonian town of Narva?

“There is no one-size-fits-all answer to what the United Kingdom is actually capable of,” concludes Keir Giles of Chatham House, “because there are so many different situations under which it could be challenged by Russia.”

As a society, the UK – unlike Poland, Finland and the Baltic States – is unquestionably not ready for war. Even serious preparations for such an eventuality would be both expensive, unpopular and politically risky.

But Mr Giles of Chatham House offers some sobering advice to the British public: “Recognise that the rights and freedoms and prosperity that they take for granted are in fact under threat and that freedom does not come for free.”

“And understand that lives will have to change. And this is not the fault of the current government or even its predecessors — it’s their fault that it is so expensive, but the root cause of the problem is in Moscow.”

Top image credit: Ministry of Defence /PA Wire/ Getty Images. (Lead image shows soldier in non-combat scenario)

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