While Nato leaders will refuse to provide a timeline for Ukraine’s membership, they will offer what is being described as a “bridge” or “path” to accession as a show of support for the process.

A package of support, currently under discussion, will highlight Ukraine’s “ability to choose its own future” and demonstrate that the “path to membership is getting shorter” as it defends itself against Russian aggression, two diplomats said.

Nato first agreed that Ukraine could become a member in 2008, but has never finalised a timeline or accession process.

Member states have since agreed that Kyiv will not be allowed to join the alliance while at war with Russia, given that it would trigger the Article 5 mutual defence clause.

In Vilnius, Britain and France pushed for the word “invitation” to be included in the summit’s final statement, to reaffirm that it was a political impediment and not a decision blocking Ukraine’s membership.