File Photo: Britain s Prime Minister Boris Johnson addresses his Cabinet during his weekly Cabinet meeting in Downing Street, London on Tuesday, June 7, 2022. AP
In an economy-focussed speech in Blackpool, northwest England, Johnson said Russia's invasion was largely to blame for a huge spike in energy prices that is fuelling a cost-of-living crisis in Britain.
But any attempts to institute a ceasefire now in Russian President Vladimir Putin's favour would return to haunt the West, the prime minister said.
"Never mind that abandoning the Ukrainians would be morally repugnant, since they are the victims and they have an absolute right to defend a free and independent country," Johnson said.
"We are simply not in a position to tell them what to do."
He did not identify anyone pushing for a peace deal. But last week, French President Emmanuel Macron drew criticism for arguing the West should "not humiliate Russia" and instead give Putin a diplomatic "exit ramp".
If Putin can win a ceasefire and grab a slice of Ukraine, he "would be able to continue to twist the knife in the wound, the crocodile would simply come back for more, and he would be able to claim that his aggression and his violence had paid off", Johnson said.
"That would be a disaster for Ukraine and all the other parts of the former Soviet Union that he might attack," as well as to vulnerable countries beyond Europe, he said.
"That would open the door to further conflict, further instability, further global uncertainty and further economic misery."