British Prime Minister Keir Starmer arrived in Ukraine’s capital on Thursday, promising to support the country’s security for the next 100 years, just days before Donald Trump is set to become the U.S. president.

The British government announced that Starmer and Ukrainian President Volodymyr Zelenskyy will sign a "100-Year Partnership" agreement in Kyiv. The agreement will cover areas such as defence, science, energy, and trade.

Starmer's visit to Ukraine was unannounced and marks his first trip to the country since he became prime minister in July. He had visited Ukraine in 2023 when he was still the opposition leader and has met with Zelenskyy twice in London since taking office. The war will reach its third anniversary next month. The Italian defence chief was also in Kyiv on Thursday, just two days after Germany's defence minister visited and three days after Zelenskyy spoke with French President Emmanuel Macron by phone. 

The rush of diplomatic activity coincided with Trump's inauguration on Monday, which is anticipated to mark a shift from the previous U.S. administration's commitment to supporting Ukraine for as long as it takes to defeat Russia. Additionally, Trump has stated that he wants Europe to contribute more to Ukraine's aid.

Starmer arrived on a gloomy, icy morning at the Kyiv railway station. “We’re a long way into this conflict,” Starmer said. “We mustn’t let up.”

During their visit, Starmer and Zelenskyy placed flowers at a memorial wall for those who have died in the war. The wall, located outside St. Michael’s Golden-Domed Monastery in Kyiv, is covered with photos of the fallen and stretches for an entire city block. It has become a place where families come to honour their loved ones. Starmer also visited a Kyiv hospital that specialises in treating burn victims.

Later, while Starmer was meeting with Zelenskyy at the presidential palace, debris from Russian drones shot down by Ukraine’s air defences caused damage to a car and a building in another part of Kyiv, as reported by the city’s administration chief, Tymur Tkachenko. One of Ukraine's largest military allies, the United Kingdom, has trained over 50,000 Ukrainian troops on British territory and promised 12.8 billion pounds ($16 billion) in military and civilian assistance since Russia's full-scale invasion three years ago.

For Ukraine's postwar economic development, Starmer is set to announce an additional 40 million pounds ($49 million). However, the United States plays a far larger role than the United Kingdom, and there is significant doubt regarding the future of American assistance to Ukraine after Trump assumes office on January 20. The president-elect says he wants to end the war quickly, has objected to the cost of U.S. aid to Kyiv, and plans to meet with Russian President Vladimir Putin, whom he has long admired.

Ukraine's allies have been working quickly to provide as much support as they can before Trump's inauguration. Their goal is to strengthen Ukraine’s position for any future peace talks to end the war. Zelenskyy has stated that during any peace talks, Ukraine will need guarantees about its protection from its much larger neighbour. Ukraine is "never again vulnerable to the kind of brutality inflicted on it by Russia," which took Crimea from Ukraine in 2014 and tried a full-scale invasion in February 2022. Britain claims its 100-year vow is part of that assurance. The agreement ensures that both sides will work together on defence,, focusing mainly on protecting maritime security from Russian activities in the Baltic Sea, Black Sea, and Sea of Azov. It also covers joint technology projects, including drones, which have become important weapons for both sides in the war. Additionally, the treaty includes a system to track Ukrainian grain stolen by Russia and exported from occupied areas of the country.

“Putin’s ambition to wrench Ukraine away from its closest partners has been a monumental strategic failure. Instead, we are closer than ever, and this partnership will take that friendship to the next level,” Starmer said ahead of the visit. “This is not just about the here and now, it is also about an investment in our two countries for the next century, bringing together technology development, scientific advances and cultural exchanges, and harnessing the phenomenal innovation shown by Ukraine in recent years for generations to come.” Zelenskyy mentioned that he and Starmer would also talk about a plan suggested by France's Macron. This plan might involve troops from France and other Western countries being stationed in Ukraine to supervise a ceasefire agreement.

Zelenskyy has stated that any such plan should also include a timeline for Ukraine to join NATO. While NATO's 32 member countries agree that Ukraine will join eventually, this will only happen after the war ends.

Trump has expressed support for Putin's view that Ukraine should not become part of NATO. As the war approaches its third year, both Russia and Ukraine are trying to make gains on the battlefield before possible peace talks. Ukraine has launched a second offensive in Russia's Kursk region, where it is struggling to keep control of land it seized last year. Ukraine has also increased its drone and missile attacks on Russian weapons sites and fuel depots. Russia, on the other hand, is slowly capturing territory, but at a high cost in casualties, along the 600-mile (1,000-kilometer) front line in eastern Ukraine. Russia is also intensifying attacks on Ukraine’s energy infrastructure, aiming to leave Ukrainians without heat and light during the cold winter months. A large Russian missile attack on Wednesday led to power grid shutdowns in several areas of Ukraine.