Britain and America must give Ukraine the weapons it needs to “win” against Russia before a pivotal winter of fighting, the Foreign Secretary has said.

Ahead of crunch talks in Washington on long-range missile use, David Lammy told The Telegraph the coming months were “crucial” in helping Kyiv get in a winning position.

Talks between Sir Keir Starmer and President Joe Biden in the White House on Friday are expected to include discussions on whether to let Ukraine fire Storm Shadow missiles into Russia.

It came as Vladimir Putin warned Nato and Russia would be at war if Kyiv was allowed to use longer-range weapons.

It is understood Ukraine only has permission to fire the missiles, which have a range of around 150 miles, into Russian-held Crimea and near the Russian border.

Volodymyr Zelensky, the Ukrainian president, has been publicly lobbying for a change in position for weeks, this week demanding a “strong decision” on the issue.

The US has so far held back permission to fire the missiles, made by the UK and France with US components, into Russia over fears of military escalation.

In an interview with The Telegraph in Kyiv, Mr Lammy stressed the importance of giving Ukraine what it needed to win the conflict.

Mr Lammy said: “This is a crucial period in the fight because you are setting things up to stop Russia getting the advantage over winter.

“We are here also, of course, at a time when it is crystal clear that Russia is escalating with its friend Iran, taking a consignment of ballistic missiles. Ballistic missiles that will be used in the winter, sadly, against the Ukrainian people and which will cost lives.

“So, of course, we’re here to strategise, to understand how we can put Ukrainians in a position to win and what is needed.”

On Thursday Putin warned Nato would be “at war” with Russia if the West let Kyiv use longer-range missiles.

The Russian president told a state television reporter: “This would in a significant way change the very nature of the conflict.

“It would mean that Nato countries, the US, European countries, are at war with Russia.”

It comes as the Ministry of Defence said on Thursday that Royal Navy ships had shadowed a Russian attack submarine through the English Channel. RAF jets were also scrambled to monitor two Russian aircraft operating near UK airspace.

In a press conference earlier this week, Mr Lammy and Antony Blinken, the US secretary of state, insisted that Iran’s move to give ballistic missiles to Russia had “clearly changed the debate”.

Speaking to The Telegraph, Mr Lammy also called for an increase in defence spending, adding to pressure on the Treasury to approve an uplift soon.

The debate over Storm Shadows comes as Ukraine fights to hold on to land grabbed in a surprise incursion into Russia’s Kursk region in August.

Elsewhere in the conflict Russian troops are advancing slowly in Ukraine’s Donbas region, setting up a critical autumn and winter in the conflict.

1,000 Russian troop casualties a day 

UK estimates have suggested around 1,000 Russian troops are killed or injured each day.

The total Russian casualty count for the full-scale invasion which began in February 2022 is believed to now exceed 600,000.

Mr Biden said this week that discussions about changing how Ukraine can use long-range missiles were under way within the US administration.

Whitehall is monitoring whether Mr Blinken’s apparent openness to a switch in position is matched by the leaders in the US Defence Department and White House’s National Security Council.

UK Government figures have attempted to dampen down speculation there would be an announcement on Friday. Both Mr Lammy and Mr Blinken have pointed to discussions at the UN General Assembly later this month.

Last night two sources told The Times the US may allow Ukraine to use British and French long-range weapons but not the American ATACMS ballistic missile inside Russia.

Mr Biden, 81, has been a strong supporter of Ukraine during his four years in the White House.

But fears have been raised over the future of US support. Donald Trump, the Republican nominee, has declined to say he wants Ukraine to win.

‘The Treasury won’t like it... but I’ll fight for defence cash’

Exclusive interview by Ben Riley-Smith in Kyiv

David Lammy called for Britain to increase its defence spending amid a looming clash with the Treasury over budgets. 

In an exclusive interview with The Telegraph from Kyiv, Ukraine, the Foreign Secretary said it was time to realise that war on the European continent had changed the debate.

Mr Lammy said it was a “mistake” for the UK to have stopped spending 2.5 per cent of its GDP on defence after the Tories, adding: “We need to get back there.”

He made the intervention as Rachel Reeves, the Chancellor, attempts to juggle spending demands with the need to fill a “black hole” in the public finances in her Budget next month.

That set of announcements will include what the Ministry of Defence budget, already hollowed out by the impact of rising prices, will be for the 2025 financial year.

Earlier this year, Rishi Sunak made it official government policy to increase defence spending from around 2.3 per cent of GDP currently to 2.5 per cent by 2030.

That timeline was scrapped by Labour and replaced with a loose “ambition” to spend 2.5 per cent. There is no deadline for doing so, creating uncertainty for military chiefs.

Mr Lammy’s comments, while not stepping beyond the official UK Government position, suggest he favours a rise in defence spending lift soon, even given the wider financial pressures.

‘Mistake to move away from 2.5pc of spending on GDP’

The Foreign Secretary was asked if he wanted a timeline for reaching the 2.5 per cent target to be named and whether he hoped for more defence spending in the Budget.

He said: “Well look, I’m not going to anticipate the Budget because I do believe the fiscal discipline that’s required of this government has to be stood by if we’re serious about fixing the £22 billion hole that we’ve inherited from the last government.

“But what I would say is this. It was a mistake to move away from 2.5 per cent of spending on GDP. And when I last left office as a minister [in 2010 at the end of the last Labour government] we had 2.5 per cent of spending on GDP. We need to get back there.

“And we do have to recognise that with war in Europe we are in different times. When you’re in countries like Poland that are on the frontline of this fight and going beyond their Nato commitment, when you’re in countries like Finland where that volunteer and preparedness across the party is extraordinary, again on the frontlines of Russia’s attack, you recognise that we in the UK have more to do.

“And that’s why I’m really pleased that John Healey [the Defence Secretary] kicked off a strategic defence review, on which I’m assisting of course, straight away in coming to office.”

A defence spending rise would be costly. When they announced their promise, the Tories said that hitting 2.5 per cent by 2030 would mean spending £7 billion more that year than planned.

Other countries go further. Poland, which borders Ukraine and was singled out by Mr Lammy, spends 3.9 per cent of its GDP on defence according to the North Atlantic Treaty Organisation [Nato].

Ms Reeves has indicated that her first full Budget on October 31 will be one of “painful” decisions including some tax rises, spending restraint and welfare cuts, rather than a giveaway.

Failing to increase defence spending in the Budget, however, is sure to trigger accusations from the Conservatives that Labour’s rhetoric on Ukraine and other global conflict zones does not match its action.

Mr Lammy was speaking to The Telegraph on Wednesday evening from the Ukrainian foreign ministry after a day of meetings alongside Antony Blinken, the US secretary of state.

It was Mr Lammy’s first visit to Ukraine since he was handed the Foreign Office after Labour’s decisive general election victory in July. The visit was also the first joint overseas trip between the two top diplomats in the US and UK for more than a decade.

The journey included an overnight sleeper train into Ukraine from the Polish border, with Mr Lammy getting limited rest as the vehicle rattled its way towards Kyiv.

There was a glimpse of a memorial wall 10 foot tall and scores of feet wide carrying postcard-sized photographs of Ukrainians killed in the fighting not just from February 2022, when Russia launched its full-scale invasion, but stretching back to 2014 when Crimea was seized – a reminder that the wider conflict is now a decade old.

A blast of sirens rang out over Kyiv as the sun began to set on Wednesday night, in response to a potential missile or drone attack, the first of two such interruptions during Mr Lammy’s short visit.

Nothing materialised in the city centre either time, but it was a reminder that even in the Ukrainian capital, far from the frontline in the country’s East, tthe war is never far away.

“You realise that there is a blitz spirit here,” Mr Lammy said. “This is a national effort. It’s not just about the politicians, it’s about the whole people determined to fight for their country and stand up to this modern-day imperialism that many of us thought we saw the back end of in the last century.”

The first wail of sirens rang out as Mr Lammy and Mr Blinken were meeting face to face with Volodymyr Zelensky, the Ukrainian president. The talks were meant to last an hour but stretched closer to two.

‘Fortitude in the face of heartache’

The Foreign Secretary, 52, is in awe of the leadership that Mr Zelensky, 46, is showing. “I have huge respect for Zelensky. He’s a modern hero,” Mr Lammy said.

“His articulacy close up is immense. The sense of command of the battlefield and what is going on is immense. His fortitude in the face of heartache, obviously, on behalf of his people is brought home.

“And, of course, he takes every single second of any engagement with a western leader like myself to prosecute what more. That’s his job. And I’m quite sure when I’m retired – he’s a little bit younger than me – that he will be one of the most impressive people that I’ve met in the course of my life.”

The nod to Mr Zelensky’s persistence, delivered with a chuckle, is pertinent. For this week there has been a significant shift in US and UK positioning on long-range missile use.

For weeks, Mr Zelensky has been publicly lobbying for the West to give him permission to fire such missiles gifted to Kyiv at targets deep into Russian territory.

For Britain, that means Storm Shadow – a weapon made with the French, plus some components from the US, which has a range of around 150 miles.

It is understood the current agreement – never made public – allows Kyiv to use the missiles in Crimea, still seen by Ukraine as its sovereign territory despite being annexed by Russia, and just over the Russian mainland border if there is a clear, imminent threat.

Deeper strikes inside Russia with the weapons have been off limits. But now discussions are ongoing to change that.

Mr Lammy and Mr Blinken stuck to the same script during their visit. They were in “listening” mode, trying to understand better why Ukraine wants permission and how it fits with the overall war strategy.

In the meeting with Mr Zelensky, the three men and their key aides are understood to have explored the specifics of operations on the battlefield, talking through the fine details of how any switch in approvals could help counter the Russian invasion.

‘Put Kyiv in a position to win’

Mr Lammy accused Moscow of “escalating” the war, citing intelligence made public this week by the US and UK that Iran had gifted Russia ballistic missiles for use in Ukraine.

He said: “We are here also, of course, at a time when it is crystal clear that Russia is escalating with its friend Iran, taking a consignment of ballistic missiles. Ballistic missiles that will be used in the winter, sadly, against the Ukrainian people and which will cost lives.

“So, of course, we’re here to strategise, to understand how we can put Ukrianians in a position to win and what is needed.”

The emphasis on giving Ukraine what it needs “to win”, and the argument that it is Russia which escalated the conflict – suggesting it is therefore legitimate for the West to now react – hints at support from the Foreign Office for giving Kyiv the green light.

Is the US in the same position? Some in Whitehall closely watching developments wonder if Mr Blinken, who heads the US State Department, is more open to granting approval than his colleagues in the US Defence Department or the White House’s National Security Council, bodies that are closer to military knock-on effects of any misstep in the conflict.

President Joe Biden’s comments after his Washington meeting with Sir Keir Starmer on Friday could offer more clues. The indication is that a change in position – should it come – is more likely to be confirmed at the UN General Assembly gathering in New York later this month than this week.

Zoom out from the specifics of weapons use and there are wider, awkward questions for the new Foreign Secretary.

The full-scale invasion is well past the two-year mark, and US presidential candidate Donald Trump refused in a TV debate this week to say he wanted Ukraine to win, opting instead to say only he wants the conflict to end. With such an uncertain backdrop, the question of the West’s appetite for continued support for Kyiv still lingers.

‘Fatigue is not part of the British lexicon’

Does Mr Lammy think there could be “war fatigue” in the West? “I had an uncle who fought for the West Indian regiment in the Second World War and I’m grateful for him,” he responded, looking to the past for reassurance.

“I’m grateful for that generation, led by people like the late Queen, Churchill ... others who never used the word ‘fatigue’. They doubled down, they dug deep. And that is what’s required of this generation.

“It’s why, when you’re here in Ukraine, Ukrainians tend to refer to the UK as the sort-of ‘first friend’ of the country. It’s why we’re working on a 100-year partnership with the Ukrainians. Because we are in this for the long haul. So we don’t understand ‘fatigue’. That’s not part of the British lexicon.”

The long haul for Ukraine, when US and UK diplomats talk about it, is a road to eventual accession into the European Union and the defensive umbrella of Nato. But it is impossible to envision those steps being taken before a peace of some form emerges.

Is it too early to start discussing the possible terms of peace? “Of course the Ukrainians have begun, particularly with countries beyond – the global south – talking about the circumstances that would bring about peace,” Mr Lammy says as our conversation ends and he heads for his end of trip press conference. 

“But they have been always really clear about this. The starting point is that Russia leaves and we support them in that endeavour.

“The mainstay of what we talked about on this trip is really the next horizon, these next four, five, six months into the spring and making sure that Ukraine is in the strongest position it can be to win.”

Mr Zelensky has, to borrow a favoured Lammy phrase, been “crystal clear” about what he feels is needed to reach that position: Approval to use long-range missiles in Russia.

By the time winter arrives, and temperatures plunge in Ukraine, a decision on that, and the reveal of Ms Reeves’s first Budget, will likely have happened.

Both will go some way to revealing how far Labour’s tough talk is really matched by action.