Why isn't Ukraine a Nato member?

Nato originally offered Ukraine eventual membership back in 2008, and after Russia's annexation of Crimea in 2014, Ukraine made joining Nato a priority.

But this hasn't happened, mainly because of Russia's long-standing opposition to such a move.

Russia fears Nato is encroaching on its territory by taking on new members in eastern Europe, and that admitting Ukraine would bring Nato forces into its backyard.

Ukraine's President Zelensky has now accepted his country cannot join Nato at present, saying: "It is clear that Ukraine is not a member of Nato. We understand this."

The UK Prime Minister Boris Johnson made the same point, saying, "There is no way Ukraine is going to join Nato any time soon".

One of Russia's demands before the invasion was that Ukraine should never be allowed to join - something the alliance had refused to support.