Zelensky arrives off the back of two diplomatic wins this week: US President Donald Trump’s decision to finally apply further sanctions against Russia, and the European Union agreeing to fund a Ukrainian budget hole.
Sir Keir is hoping to maintain the momentum by increasing the pressure on Moscow to negotiate an end to the war.
Among the leaders attending Friday’s summit will be Nato Secretary General Mark Rutte, Denmark’s Prime Minister Mette Frederiksen and Netherlands’ Dick Schoof. Others including French President Emmanuel Macron will join virtually.
Sir Keir will urge leaders to ramp up the provision of long-range weapons after a successful attack on a chemical plant in Bryansk, Russia, using British-supplied Storm Shadow missiles.
“The only person involved in this conflict who does not want to stop the war is President Putin,” Sir Keir said.
“And his depraved strikes on young children in a nursery this week make that crystal clear,” he added.
Two children were among at least seven killed in a wave of Russian strikes on Ukraine, which hit a nursery in the second biggest city Kharkiv.
Sir Keir will also announce 100 additional air defence missiles will be delivered to Ukraine earlier than planned, as outlined in a £1.6bn deal struck between the UK and Ukraine in March.
“Time and again we offer Putin the chance to end his needless invasion, to stop the killing and recall his troops, but he repeatedly rejects those proposals and any chance of peace,” Sir Keir said.