There is a close relationship between the need for significant defense reforms and the political decision to join Ukraine in NATO, said British Ambassador to Ukraine Melinda Simmons.

"I think there's an element of political decision in all of it. There always has been and always will be. I don't think that's discounted. But I also think that there's a close relationship between the need for essential reforms and the political decision because if you don't make progress on those essential reforms, you provide a very convenient reason for those who may be less interested in expanding membership not to continue," Simmons told Interfax-Ukraine.

The ambassador said the requirement for the interoperability of the Ukrainian army with NATO armies was met even before the start of a full-scale war, but there is a need for institutional reform of defense mechanisms in Ukraine.

"Because it's really clear, and, frankly, the one thing that nobody wanted - this war to happen - has shown how capable the Ukrainian Armed Forces can be of operating with NATO standard equipment. But we actually did know that before the war. I'm sorry to say they had to be tested on it. But we did already know the interoperability was not the issue, in the sense that was already being met. The issue was institutional reform of defence mechanisms, defence procurement, defence human resources, etc., where we all know there's quite a lot of work still to be done," Simmons said.

The ambassador said this reform is necessary not only for the issue of Ukraine's accession or non-accession to NATO, it is important in order to have a strong Armed Forces in the future.

"Those people don't just need to be paid, they need transparent career opportunities, they need corruption to be weeded out in terms of defence procurement, so they can trust that these things are being procured and tracked in the right way. That makes the institution stronger, which in turn means it can support its army better," she said.

Simmons said this work is still ongoing with the Ukrainian Ministry of Defense.

"And I continue to think it is really important work. And my sense from Defence Minister [Oleksiy] Reznikov is that he thinks it's important too. It's just hard to prioritise it right now," she said.

The British Ambassador said that NATO is in principle open to countries that can collectively play their role in European security.

"I think it's right to have the discussion about security guarantees. I also think it's right that we will all collectively need to work out what that looks like. I can absolutely see why the Ukrainian authorities have done it [applied to join NATO]. I think it's really good to have the conversation about steps towards it. I suspect that the majority of countries are going to continue to want to focus on what they need to do right now," she said.

However, Simmons said she felt it was right to have a discussion about security guarantees for Ukraine. According to her, it will be necessary to determine how they will look.

"It's really great that the Office of the President has been promoting the conversation about it. I still think we have some way to go in working out what it looks like, whether it is about weaponry and making sure that Ukraine just looks too difficult to invade in the future in terms of its own capability, or whether it needs security guarantees that look political. The formal part of it is still a conversation that we're having. But there's no question that we support the conversation in principle right now," the diplomat said.