Sitting down with the Guardian in London, Volodymyr Zelenskyy seems cheerful. More than four years after Vladimir Putin’s full-scale invasion, he believes Europe’s biggest war since 1945 appears to be slowly turning in Ukraine’s favour. The military situation is the most promising it has been for Kyiv for two and a half years, Zelenskyy says. “We can’t say Russia is losing this war. But we can say they are losing the initiative each day, day by day,” he insists.

Over the past week the Kremlin has suffered a series of setbacks. Long-range Ukrainian drones have hit Putin’s home city of St Petersburg, setting fire to oil terminals and sending smoke billowing above the skyline. Similar attacks have crippled occupied Crimea. A key supply road is littered with burning lorries and tankers and the peninsula seized by Russia in 2014 is experiencing severe fuel shortages.

Meanwhile, on the eastern battlefield, Russia’s grinding advance has come to a near halt. According to Zelenskyy, who since 2022 has consistently said he believes that with sufficient support Ukraine can defend against its invader, the Kremlin is losing more than 30,000 soldiers a month, with 23,000-24,000 killed and the rest “heavily” wounded. The true figure, he suggests, could be even higher. “Totally, this is a very big number. It means that they are not winning the war,” he points out. Ukraine has lost service personnel too on a lesser scale.

Moscow’s war may look stuck, but its destruction continues and it has in recent months intensified its aerial attacks on Ukrainian towns and cities with the apparent goal to terrorise those not involved in fighting. One attack last Tuesday featured 73 missiles and 656 drones. Eighteen people were killed in Kyiv and Dnipro, including a three-year-old boy. He was entombed under the rubble of an apartment block. According to the city’s mayor, the Russians are deliberately using cluster munitions in built-up areas.

Last week, Zelenskyy wrote an open letter to Russia’s president, suggesting a face-to-face meeting to wind down this terrible conflict. Speaking on Friday at the St Petersburg economic forum, Putin rejected the offer. He characterised the letter as “rude” and said Russia’s territorial demands – the Donbas region and two southern Ukrainian provinces – were unchanged. He also insisted Russian forces were going forward across all parts of the frontline, telling them: “Keep working, brothers.”

Putin’s implacable stance has led some observers to wonder if he is delusional, or being fed wrong information by his commanders. Zelenskyy says these theories are plausible, but he stresses that “the reason he’s lying doesn’t matter”. Putin, he adds, has lied about the war from the beginning, claiming it was necessary to seize Ukrainian land to “rescue” Russian speakers. His lies are a glue, used to “join” different elements in Russian society together, he thinks.

On the international stage, Russia has experienced several recent political defeats. In April, Putin’s closest ally in Europe, Viktor Orbán, was trounced in Hungary’s general election. Recent Russian efforts to support pro-Kremlin candidates in Moldova and – over the weekend – in Armenia also failed. “They are losing influence in different countries, including in Azerbaijan,” Zelenskyy says. He adds: “They are isolated inside Europe and from the United States also. So they are alone.”

Donald Trump began his second term in 2025 saying he would end the war and Zelenskyy has carefully praised US diplomatic efforts, despite his bruising encounter in the Oval Office, last summer’s pally summit between Trump and Putin in Alaska, and cuts to US aid for Kyiv. “I always said to President Trump that Putin is lying. He plays games with you, with the White House,” Zelenskyy says, adding that he is grateful to Americans for their “strong support” for his country.

Ukraine’s president admits that Washington’s attention has moved to the Middle East. “Of course, from the very beginning of the war with Iran their focus shifted,” Zelenskyy says of the Trump administration. He understands why the US has used up “so many missiles and weapons” in its war of choice with Tehran. He observes wistfully that Kyiv – unlike the US’s Gulf allies and Israel – never received “that volume of support”. “It’s a pity,” he says.

Since 2022 Ukraine has transformed itself into a drone superpower. Once a supplicant for western military aid, Kyiv has grown into a hub for military industrial production and technical innovation. Several Arab countries have sought its help in shooting down Iranian Shaheds. The most important weapon Ukraine now lacks, Zelenskyy says, are US-made Patriots. They are the only system capable of shooting down Russian ballistic missiles, which rain down nightly on sleeping Ukrainian civilians.

On Sunday, Zelenskyy held talks in Downing Street with Keir Starmer, Germany’s chancellor Friedrich Merz and the French president Emmanuel Macron. Zelenskyy says he renewed a call to his European allies to “close” Ukraine’s skies – in other words, to help Ukraine fend off large-scale Russian drone and missile attacks. As well as antiballistic interceptors, he wants financial support to transform Ukraine’s mobilised armed forces into a European-style contract army.

He recognises that Patriot missiles are expensive, costing $4m each. The UK does not have its own antiballistic missile programme. London, Paris and Berlin and other EU states should work together to build an alternative to the US version, he believes. In return, Ukraine is ready to share its hard-won experience of drone warfare with its European friends. “The UK is among them. And Nato is very interested in it. This is priceless information. There is a huge volume of it,” he says.

Zelenskyy is reluctant to be drawn on future military operations. But long- and mid-range drone attacks have made the return of Crimea – annexed by Russia in 2014 – a tantalising if distant possibility. Ukraine’s forces are busy destroying the peninsula’s logistics, and hitting other military and energy targets all across occupied southern Ukraine, he says. “It’s all about critical infrastructure. This helps them to militarise our Crimea. We are working on it,” he adds.

For a long time many Russians have tried to ignore the war raging across the Ukrainian border. Zelenskyy says the purpose of long-range strikes – which have seen drones buzzing above apartment blocks in greater Moscow and St Petersburg – is to make residents “feel” what war means. He adds: “Victory in this war is when Russian society recognises that the war is awful, that the war is a tragedy not for someone, somewhere, but for themselves. And I think this is the momentum.”

In May, the Russian oligarch Roman Abramovich secretly travelled to Kyiv for talks with Zelenskyy. Zelenskyy says he told Abramovich he would never give up the Donbas region, as Moscow wishes. Explaining the meeting, he says: “I think there are different people around Putin. Half of them want to continue this war. Half want to stop. And I think that people who are from business, they understand that the economy is in terrible situation in Russia. It’s very close to collapse.”

Zelenskyy spoke to the Guardian shortly before going to see King Charles. The two men appear to have developed a warm and trusting relationship. Zelenskyy has previously revealed that the monarch urged Donald Trump during his state visit to the UK last year to support Ukraine, something the US president has been distinctly reluctant to do. If the war continues to go well, could the monarch one day visit Zelenskyy’s own palace in Kyiv?

Ukraine’s president grinned at the question. He nodded his head enthusiastically. “You know today in the morning when I spoke by phone with my wife [Olena], with all respect to Keir [Starmer], my wife said best regards to the king. And then to the prime minister,” he confesses. “Ukraine loves his majesty. I would like to invite him to Kyiv very much. Maybe this year. I don’t know from the point of security but of course we want to see him.”