Ukraine has said it may accept neutral country status if the West provides binding security guarantees, abandoning its quest to join NATO.
President Zelenskyy has acknowledged that his country cannot join the military alliance, saying "that's the truth we much recognise".
Ukrainian negotiators said at this week's peace talks in Istanbul that Kyiv might accept neutrality if there was an international agreement with western countries such as the US, France and the UK providing binding security guarantees.
Samuel Ramani, associate fellow at the Royal United Services Institute, told Euronews he found the idea "wholly unrealistic".
The role of security guarantor, he said, would be akin to NATO's Article 5, which would involve risking going to war with Russia to defend Ukraine, something no state is prepared to do now.
"This whole security guarantor concept is quite murky and it's probably unenforceable," he argued.
Watch the interview with Samuel Ramani in the video player above.