The 30-mile stretch of land that will dictate the future of Europe

The Ukrainians seem to believe that they have managed to persuade Donald Trump to champion a peace plan that better meets their needs, but convincing Vladimir Putin to accept it is likely to be an uphill struggle.

A crucial issue is the future of the portion of the contested Donetsk region still in Ukrainian hands. Kyiv is trying to avoid making its surrender a price of peace, but this is one demand Moscow seems unlikely to abandon.

Just what is it that makes it so important?

This industrial region has long been at the heart of tensions between Russia and Ukraine. About three-quarters of its population spoke Russian instead of Ukrainian, although this did not mean that they wanted to swap Kyiv for Moscow.

Some did, though, after the 2014 Revolution of Dignity saw the government under Viktor Yanukovych toppled and a pro-Western one installed in its place. Along with Russian nationalist allies, they began local revolts, which Moscow would in due course support and take over, leading to eight years of undeclared conflict and then the 2022 invasion.

Its coal mines and steel mills may have some value, but its real significance is political and strategic. Russia now controls four-fifths of Donetsk region, but Kyiv still holds the north-western corner. Crucially, this territory is anchored by the 30-mile wide “fortress belt” comprising four cities, Kramatorsk, Slovyansk, Druzhkivka and Konstantynivka and a dense network of trenches, bunkers, minefields and razorwire around them.

While Russian forces are nearing Konstantynivka, given that it took them 18 months to reduce their previous objective, Pokrovsk – and fighting is still going on within city limits – one British Ministry of Defence source suggested to me that, “barring some unexpected collapse of Ukraine’s forces… the ‘fortress belt’ could be expected to hold for a couple of years”.

Yet Putin is pressing for Kyiv to hand it over without a fight. First, he just wanted outright surrender. Then, in the recent 28-point plan, the issue was slightly fudged by suggesting that the area could be surrendered, yet demilitarised, such that Russian troops would not be stationed there.

In theory, this should offer Kyiv some reassurance given that one of its concerns is that, once past the fortress belt, Russian forces could push easily into the neighbouring Kharkiv region. However, not only would this be hard to verify, there would be loopholes for Moscow to exploit.

Cities need policing, for example, and part of Russia’s law enforcement apparatus is the Rosgvardiya. As well as riot police and patrollers, this security force includes militarised units with armoured vehicles and artillery. Allowing them into the disputed territory is the next best thing to inviting in the Russian army.

For Ukraine this is more than just a strategic calculation, though. This territory has been fought over for years. Slovyansk is where the undeclared war in eastern Ukraine essentially began, when the Russian nationalist Igor “Strelkov” Girkin led a 50-strong force of militants to seize it in April 2014.

Even if he wanted to, could Volodymyr Zelensky give up lands steeped in the blood of Ukrainian defenders? One Kyiv insider told me that if he tried to give orders for such a retreat, “he would not survive it”. He didn’t mean just politically.

The European version of Trump’s plan took out references to surrendering this territory, instead offering a bland commitment to negotiations over territorial swaps after a ceasefire. Given that such negotiations could be dragged out forever, no wonder, as a Russian political observer noted, “this is taken in the Kremlin to be a refusal – and Putin simply cannot take no for an answer”.

Like the myth of Caesar burning his boats on first landing in Britain, symbolising that he was there to conquer or die, Putin has chosen to make total control of Donetsk region one of his apparently non-negotiable demands.

While it is clear why he would want Ukraine to surrender this territory, not least to humiliate Zelensky and his Western backers, why has Putin apparently chosen to back himself into a corner over Donetsk? He formally annexed the whole region in 2022, including those portions not under Russian control, but he also claimed the two southern regions of Zaporizhzhia and Kherson and seems willing to allow some of the former and most of the latter to remain under Kyiv’s authority.

To some in Kyiv, it is precisely because he knows Zelensky could not make such a concession, and is a cynical ploy to make the Ukrainians look like the obstacles to peace in Donald Trump’s eyes.

There may be some truth to it, but the main reason likely lies in Putin’s desperate need for something he can claim to be a triumph. Along with ensuring Ukraine doesn’t join Nato, “protecting” the Russian-speakers of eastern Ukrainian has been one of his avowed goals from the start of his war.

With perhaps 1.3 million dead and wounded, and an economy sliding into recession, all because of his war, Putin may have convinced himself that he needs this last victory to convince Russians it was all worth it.