Boris Johnson has indicated he will attend the G20 summit in Bali later this year even if “pariah” Vladimir Putin is at the event.
Indonesia is hosting the summit in November and the Russian President, as a member of the Group of 20 leading economies, is invited.
The Prime Minister said that boycotting the event in protest at the invitation extended to Mr Putin would hand a “propaganda opportunity” to the Russian leader.
He said the West needed to attend the meeting to help win over nations who might otherwise fall under the influence of Russia or China.
Speaking to reporters accompanying him on a trip to the Nato summit in Madrid, Mr Johnson said: “I would be absolutely amazed if Putin goes in person. He’s a pariah figure.”
Mr Johnson said he believed Mr Putin was “highly unlikely to go” to the summit in person “for all sorts of reasons”.
He added: “There is a very difficult question about the G20. Yes, he’s been formally invited, I don’t think he will go.
“The question is: do we, as the Western countries, vacate our seats at the G20 and leave the whole argument to China, to Russia?
“Much of the conversation with the G7 has been about, are we doing enough to win over the swing voters?
“What can we do with the middle of the congregation? The people who look at Ukraine and have mixed feelings, we need to be doing more to win them over, we need to be making our case, and you know who those countries are.
“I think if you vacate something like the G20, you risk just handing the propaganda opportunity to others.”