It’s no secret we are already at war with Russia – Putin must be hit with every trick in Britain’s book

Yet again this week, President Trump set Europe’s strategic challenge. Despite reaffirming US commitment to Euro-Atlantic defence once allies pledged to invest more ourselves, his new national security strategy pivots to the Pacific while his Ukraine peace plan negotiates European security without European input. Europe might not be on our own, but we need the capability to be self-reliant. And fast.

The Royal Navy announced this week its goal to be war-fighting ready by the end of the decade. The army and RAF have similar ambitions. But the leisurely timeline for reaching 3.5 per cent GDP by 2035 will neither deliver the resources necessary nor impress Vladimir Putin, determined to keep his war machine and economy rolling even with a Ukraine ceasefire.

As national security adviser, I dealt with the Salisbury poisonings, about which Lord Hughes’s inquiry reported last week. It was a turning point. After years of inadequate responses to Syria, Crimea, MH17, Litvinenko and Russian subversion, we decimated Russian intelligence capability with the largest collective expulsion of Russian intelligence officers in history and imposed genuinely painful sanctions. Yet even that success was fundamentally defensive. We responded to an attack that had already been executed. We established consequences but not deterrence.

The truth is, we are already at war: conventional war in Ukraine, hybrid war elsewhere. Putin certainly believes he is at war with us. As I told parliament recently, Russia could bring Britain to a standstill with a cyber attack on our food distribution system, coupled with an information operation to create panic buying and public disorder. No missiles or troops required.

Part of the response is national resilience by hardening critical infrastructure, supply chains and communications networks. But resilience without offensive capability is the modern Maginot Line: static defence against an enemy practising offensive manoeuvres. As Yvette Cooper set out this week, Russia continues shadow fleet operations, cable sabotage, GPS manipulation and subversion of our democratic systems. We respond with investigations and attribution. Attribution does not deter.

Sun Tzu wrote: “The supreme art of war is to subdue the enemy without fighting. Attack him where he is unprepared, appear where you are not expected”. Nato too should manoeuvre in this grey zone.

We could target Russian vulnerabilities, including ageing energy infrastructure, dependence on Western systems, an isolated Kaliningrad enclave, and concentrated military-industrial facilities. We should deny insurance to Russia’s shadow fleet, impound vessels in Nato waters and pass extra-territorial legislation enabling Nato navies to respond to cable attacks in international waters. We should demonstrate our capability to mount cyber attacks against Russian energy and military infrastructure. And we should apply systematic pressure to its Kaliningrad enclave, which relies on land and sea access via Nato territory.

Won’t this provoke Russian escalation? Putin invaded Ukraine, uses chemical weapons, shoots down civilian aircraft, sabotages infrastructure, assassinates dissidents and subverts democracy, all without facing severe consequences. Yet Nato is mesmerised by fear of retaliation, while Russia follows Lenin’s doctrine of continuous escalation until met with steel. The risk is not that we provoke attacks. They are attacking us already. The risk is that failing to impose a price invites further aggression.

Some argue this requires unanimous European support we cannot secure. Wrong question. Several allies – Nordics, Baltics, Poland – who understand the threat are ready. France and Germany will follow once we demonstrate resolve. Coalitions of the willing have repeatedly moved the Nato consensus. Waiting for permission guarantees continued Russian aggression.

Putin regards the UK as Russia’s most implacable adversary. Let us embrace that. Britain should lead this hybrid campaign for Europe. Our world-class intelligence services, special forces and cyber force can deliver strategic effects through precision operations. Our strategic culture is not paralysed by fear. We understand that credible deterrence is offensive, not just defensive, striking where Russia is vulnerable, forcing them to defend everywhere, imposing costs through means difficult to predict. This is a hybrid war of manoeuvre. Europe needs a nation willing to spearhead it. Britain should be that nation.

Lord Sedwell is a diplomat and senior civil servant who has previously served as national security adviser and cabinet secretary