Rishi Sunak said he wants to see Nato’s commitment to inducting Ukraine as a full member of the alliance “reaffirmed” during discussions with leaders at the Vilnius summit.
The Prime Minister arrived in the Lithuanian capital on Tuesday as he prepares for a flurry of meetings with world leaders across two days.
The pressing issues are set to be about Nato expansion and cajoling member states to meet the goal of spending 2% of gross domestic product (GDP) on defence.
Speaking to reporters on the plane journey from London, Mr Sunak said the UK, as well as the leadership of Ukraine, recognised that Kyiv would not join the defensive alliance “while they are in the midst of a conflict”.
But he said his Government “stands by” the conclusion of Nato’s 15-year-old pledge to put Ukraine on a path to membership.
Britain is keen to see Ukraine’s membership fast-tracked, arguing much of the military reforms asked of it are being witnessed on the battlefield in its fight against Russia’s invading troops.
The US and Germany are said not to be on the same page as Britain, however.
Mr Sunak said: “I’ve always said that Ukraine’s rightful place is in Nato and that we stand by the language of Bucharest in 2008.
“I think what is important at this summit is that that commitment is reaffirmed and also that there is demonstrable progress towards that goal.”
Nato secretary general Jens Stoltenberg, who has had his tenure extended for 12 months, has said he is confident the summit will send a “positive message” to Ukraine about its path to membership.
The Prime Minister appeared to confirm reports that conversations have taken place with allies to provide Ukrainian president Volodymyr Zelensky with non-Nato security guarantees.
According to the Daily Telegraph, the UK, US, France and Germany – dubbed The Quad – are looking to finalise an “Israel-style” security deal to provide Kyiv with a multi-year plan to defend itself from Russian aggression.
The paper reported that it would be similar to a military and financial pact that Washington has with Tel Aviv to afford it protection in the Middle East.
Conservative Party leader Mr Sunak said Britain had played a leading role in the discussions since he put the issue of multilateral Western security assurances on the table during his speech to the Munich security conference in February.
He told reporters he was “keen to try and get this over the line”.
“I think it is something that we in the UK have taken a lead on, it is something I’ve spoken a lot to fellow leaders about over the last few months,” he said.
“Those conversations are ongoing so we need to keep having them, but that is the purpose of them.
“It is to demonstrate that long-term commitment from a broad group of countries. It is distinct from the Nato conversation and I think it will send a very strong signal of deterrent to (Russian President Vladimir) Putin, that he can’t wait people out, in terms of this conflict. I think it is important and valuable.”
In a message aimed at Mr Putin, Mr Sunak said: “We are with Ukraine for as long as it takes.
“That is why the security assurances are important because what Putin needs to understand is there is no point in just waiting out the West.
“Everyone is in it for the long haul and any thought he had that this would be over quickly has already been proved to be false.”
Downing Street said Mr Sunak would use the Vilnius summit to press home the importance of increasing Nato’s defence spending in order to ward off Russian “tyranny”, urging member states to meet the 2% GDP target.
Upon arrival in Vilnius, the Prime Minister was forced to defend the Government’s investment in defence.
Following suggestions Britain could lose influence due to potential cuts to the Army, he told broadcasters the UK “should be incredibly proud of the leading role” it plays in global security.
Mr Sunak’s first bilateral meeting after arriving at the summit was with Turkish president Recep Tayyip Erdogan.
It follows a breakthrough with Ankara, brokered by Mr Stoltenberg, to remove Turkey’s objections to Sweden being admitted to Nato.
A full allies meeting of Nato is to take place on Tuesday afternoon, with Mr Zelensky due to travel to Vilnius on Wednesday to join discussions.
