It was meant to take ten days – 1,460 days later, Russia's stuck in Ukrainian meatgrinder

However, for war-weary Ukraine, this is the 12th year of strife with Russia, which first snaked its way into the Crimea on February 26, 2014. Much of the industrial Donbass region in the east was swiftly devoured the following month by Kremlin-backed forces, who shot down an innocent airliner flying over eastern Ukraine, killing all 283 passengers and 15 crew aboard. Russia has never apologised.

Ukraine has changed our understanding of the modern battlespace. Clearly defined front lines are a thing of the past, with a wider, shifting ‘grey zone’, hundreds of miles wide, where civilians as much as soldiers are the targets. Much of the destruction is caused by unmanned air, land and sea machines, which evolve in technological terms, on a daily basis.

Long range, high-speed missiles are still difficult to intercept, with the result that both Moscow and Kyiv rely on the formula that if you launch enough, some will get through. Ukraine is experiencing great success in hitting Russia’s ammunition warehouses, oil terminals and power stations.

Each side has refined its tactics, shifting away from human wave assaults towards small infiltration groups to probe minefields, conduct reconnaissance and take prisoners. However, Putin is impatient for results and his compliant generals are afraid to stand up to him. This is why Russian combat losses, often of prison convicts, poorly-trained conscripts or third country nationals from Africa, Cuba or North Korea, have been so high.

Putin sees this clash as his version of the Great Patriotic War, where the USSR defeated Nazi Germany in 1941-45 at huge cost. Stalin, a cruel dictator who presided over a regime of terror, emerged as a hero in Russian history. He is desperate to be seen in the same light, which explains why he has locked himself into a forever-war in Ukraine. Isolated from his people, he worships the idea of being a warlord. Though at present he may not be able to win the war, he equally fears peace.

Bloody conflict has become an end in itself for the man in the Kremlin. Any US-negotiated peace plan is unlikely to satisfy him. A Russia not at war would reveal angry relatives, muttering veterans, the tanking economy and questions about his leadership. For the man who could stop the conflict in an instant, peace would be more dreadful than war.

Although the combat is limited to two countries, this confrontation has spread beyond the original battlefield. Countries like Iran and North Korea have supported Russia with personnel, tanks, drones, technology and money. Meanwhile, the western ‘Coalition of the Willing’ is helping Ukraine with training, war-fighting doctrine, intelligence and weapons.

Is there a chance the conflict might spread? As after the treaty of Versailles in 1919, a poorly-drafted peace for Ukraine might encourage Putin to stray in the direction of other territorial ambitions.

Donald Trump cares little for the political consequences, only the commercial opportunities this might open in Kyiv and Moscow. Last month, the leading TV propagandist Vladimir Solovyov called for Russia to conduct more ‘special military operations’ in Central Asia and the Caucasus, meaning independent countries like Armenia, Georgia, oil-rich Azerbaijan and Kazakhstan.

At the same time, Kremlin ideologue Alexander Dugin stated that “no post-Soviet state should possess sovereignty”. The man often called ‘Putin’s brain’ argued that his master “had no choice but to restore the Russian Empire”.

Closer to home, this might indicate a swift land grab in Estonia if NATO attention was adequately distracted or the USA was sufficiently disinterested. Distractions might include assassinations, espionage, arson and cyberattacks of the kind already seen across Europe. Drone swarms launched from Russia’s shadow tanker fleet, of the kind suffered last year in Denmark and Germany, and which nearly ambushed President Zelensky off Dublin, are another danger.

Putin has already proved he is no respecter of international borders with the 2006 poisoning in London of Alexander Litvinenko and the 2018 attempted poisoning of Sergei and Yulia Skripal in Salisbury. The threat, therefore, is real and the ramifications are several. While the UK has become the self-appointed cheerleader for Ukraine, none of the conflict’s warfighting lessons have been incorporated into the current defence budget. Our current allocation of 2.4% of GDP is inadequate.

Equally, 3% by 2029-30 will not do. Only a figure approaching 5% might reverse our military decline. Our present arsenal allows us a mere eight days of the kind of intense warfare seen in Ukraine, before our ammunition stocks hit empty.

With America stepping back from international organisations like the UN and NATO, the UK can talk big about facing off against future aggressors like China and Russia. However, we do not have the personnel numbers to step up to the responsibilities beginning to the vacated by Washington DC, or even match those of our principal European military colleagues in France, Germany and Poland.

This is important, because only a credible defence budget, backed by an adequate manufacturing infrastructure and strong personnel numbers can influence our stature on the international stage, and deter our opponents.

This leads back to the fourth anniversary of the Russo-Ukraine war. Kyiv is fighting for its very survival and cannot give in. Mr Putin has too much of his personal machismo at stake to stop. Either way, the eventual result will indicate the path of wider European security, including that of the UK, for the next 50 years.