Rishi Sunak has labelled Russia as a "rogue state".
Rishi Sunak has taken aim at Vladimir Putin and Russia
The UK Prime Minister took aim at Vladimir Putin for not attending the G20 summit in Bali as a number of world leaders prepare to meet.
The summit marks the first time a British leader has met with Russian officials since the start of the Ukraine invasion in February although the Kremlin's foreign minister Sergey Lavrov will be there in Putin's place.
Writing for the Daily Telegraph newspaper, Sunak said: "Leaders take responsibility. They show up. Yet, at the G20 summit in Indonesia this week, one seat will remain vacant.
"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. He won't even attempt to explain his actions. Instead, he will stay at home and the rest of us will get on with the task at hand."
Sunak continued: "Last week, we saw the Ukrainian flag raised once again over Kherson only weeks after Putin declared that the city would be part of Russia forever. It is an historic milestone in Ukraine's fight to take back what's theirs.
"They are standing up for fundamental principles that matter to us all - the principles of sovereignty and self-determination, which are the very foundations of a stable international order."
Sunak vowed that Britain will "never back down" in its support for Ukraine.
The Prime Minister said: "But we know the Ukrainian people are still suffering terribly under the continued Russian bombardment and prolonged power blackouts in near-freezing temperatures.
"That's why when I spoke to Volodymyr Zelensky, the Ukrainian president, I made clear that Britain will never back down when it comes to supporting the Ukrainian people in the face of this brutality."