Rishi Sunak has called Russia a “pariah state” on the eve of his first meeting of the G20 in Indonesia, where he has vowed to confront Moscow’s representative in public and on the sidelines of the summit. The UK prime minister said he would take every opportunity during the summit to confront Russia’s foreign minister, Sergei Lavrov, attending in Vladimir Putin’s absence, and said that would be not only in the hall itself but at any opportunity if the two came face-to-face. “Russia is becoming a pariah state and he’s [Putin] not there to take responsibility for what he’s doing,” Sunak told reporters on the plane ahead of the meeting in Bali, where he will meet Lavrov for the first time. “But I’m going to use the opportunity to put on the record my condemnation of what they’re doing. I will do that in the hall, I will do that if I see him elsewhere and that’s the right thing to do.” Sunak said his opening words at the G20 would be to condemn Putin’s brutal war in Ukraine and said there was no suggestion the Russians were prepared to restart peace negotiations. In a separate article for the Daily Telegraph on Monday, he described Putin as “the man who is responsible for so much bloodshed in Ukraine and economic strife around the world will not be there to face his peers”. Russia’s presence has cast a shadow over the summit and put states at an impasse over a final communique, which is like to contain only weak resolutions on the economy and digital issues because of the inability of the G20 to agree a statement that would condemn Moscow’s aggression or pin the blame for economic turmoil on the war in Ukraine. Sunak said there would be a united approach towards Russia at the summit among G7 allied nations, including the US, Canada and European countries. The prime minister has been keen to stress and enhance his own public commitment to Ukraine after the turmoil in UK politics and his prior reputation when chancellor as having warned about the financial impact on the UK of undertaking harsh Russian sanctions. “I’m going to take the opportunity to unequivocally condemn the Russian state and Putin for their abhorrent and illegal war and that’s what I plan to do,” he said en route to Bali. “That’s what I believe our allies will also do.” Sunak said it was “telling” that Putin was not willing to come to the G20 in person and hear widespread criticism, though his refusal was more likely in order to avoid awkward conversations with more neutral countries such as China and India. “It demonstrates a lack of responsibility for what he’s doing,” he said. “This for me is an opportunity to unequivocally condemn Russia for their aggressive and illegal actions in Ukraine and work with our allies to do that. And that this is the opportunity that summit presents us to take advantage of that.” British officials have been pessimistic about the prospect of a communique emerging from the summit when one has not been agreed in ministerial meetings in the run-up to the G20. But No 10 has also said there is a widespread feeling that Russia’s presence should not be allowed to stymie all progress and that some words are likely to be agreed on the importance of stability in the global markets. The summit will take place in the days after extraordinary Ukrainian military advances, including retaking the strategically important city of Kherson. Sunak said it was not the role of western leaders to spell out the moment of maximum advantage for the Ukrainians to restart peace negotiations, saying only that the west had a responsibility to put Ukraine in the strongest position possible. “They will decide their approach to negotiations,” he said. “Of course they want to see, as does everybody, a peaceful resolution to this settlement but I view our job, and I think our allies are in the same place, as putting Ukraine in the strongest possible position for an eventual negotiation. And that’s our job – and ultimately the Ukrainians will then decide the basis of those talks.” Sunak admitted that a prolonged conflict would continue to have worldwide ramifications but said the timing of any negotiation had to be of Ukraine’s choosing.