Ukrainian refugees face being sent to Rwanda if they travel to the UK without authorization, Boris Johnson has said in an escalation of government plans to deport those who travel across the Channel seeking sanctuary.

During a visit to the Rwandan capital, Kigali, the prime minister also urged Nato and G7 countries not to settle for a “bad peace” in the conflict between Ukraine and Russia, saying it would lead to escalation by Vladimir Putin’s war machine.

Previously, Johnson had said the prospect of Ukrainian refugees being sent to Rwanda won’t happen, but now, it is possible.

But asked at the Commonwealth heads of government meeting (Chogm) whether Ukrainians arriving by boat could face deportation to east Africa, he said: “The only circumstances in which people will be sent to Rwanda would be if they come to the UK illegally, and thereby undermine the safe and legal routes that we have. I think we are giving 130,000 visas to Ukrainians and they have at least two very good routes for coming to this country.

“But if you come here illegally, you’re undermining all those who come here legally. And it’s crazy. So I’m afraid the answer is I suppose, yes, in theory, that could happen. But I think it’s very unlikely.”