Number 10 has pledged support Ukraine for as long as the war there lasts, despite President Volodymyr Zelensky’s suggestion the UK “has slowed down” in its support for Kyiv.

Prime Minister Sir Keir Starmer’s spokeswoman described an ongoing dialogue with Ukraine about what the country needs to repel Russian forces from within its borders.

Mr Zelensky wrote on X, formerly Twitter, on Saturday that the UK had previously shown “true leadership”, but that this had since eased.

Asked about the allegation, a Downing Street spokeswoman said: “The Prime Minister remains absolutely resolute in his support for Ukraine and in fact, on the latest situation, including in Kursk, the Prime Minister wants to set out his full admiration for the bravery shown by Ukrainian soldiers who have once again proved their spirit and determination in the face of continued Russian aggression, and shown that they will do whatever it takes to defend their country.

“It is a reminder that Ukraine has consistently exceeded expectations of what is possible and Russia continues to fail.

“But in terms of our support, again, it is unwavering. That’s why we committed to £3 billion a year in support for Ukraine to do that for as long as it (the war) lasts.”

A recent package of aid to Ukraine, confirmed in July, included 90 anti-armour Brimstone missiles, 40 de-mining vehicles, 10 AS-90 artillery guns and support for them, including barrels and spares which will help Ukraine fire another 60,000 155mm rounds, and about 250,000 50 calibre ammunition.

Mr Zelensky wrote on X: “Throughout this war, we’ve seen the UK demonstrate true leadership – in arms, politics, and support for Ukrainian society.

“This has saved thousands of lives, reflecting the strength of the UK.

“Unfortunately, the situation has slowed down recently. We will discuss how to fix this because long-range capabilities are vital for us.”

The president also wrote: “We will intensify our diplomatic efforts, insisting on bold actions and decisions that genuinely change the course of this war – leading to a just peace and a true end that we all need.

“We need all partners who can truly help to step up.

“These are the United States, the United Kingdom, France, and others.”

The Number 10 spokeswoman said the UK has “an ongoing dialogue with our allies about a co-ordinated effort between us all to do the same thing and be united in our support for Ukraine”.

Russia invaded Ukraine in February 2022.

The following month, Mr Zelensky addressed the House of Commons, via video link.

He said: “We will not give up and we will not lose.”

After a change of power in the UK, when Labour ousted the Tories earlier this year, Mr Zelensky visited Number 10, where he addressed the Cabinet.

“I ask you to show your leadership in this and please convince other partners to remove the limits,” he told the Government’s most senior ministers, including Sir Keir.

Defence Secretary John Healey also met Mr Zelensky in Odesa after the vote.

Ukrainian forces entered Russia earlier this year, in the Kursk Oblast.

The UK Government has confirmed Kyiv was free to use UK weapons in its offensive.

But the long-range Storm Shadow missiles remained off limits beyond Ukraine’s borders, the PA news agency understands.

Questioned about Storm Shadow missiles and whether the weapons could be used in Kursk, the Number 10 spokeswoman said there had been “no change in the UK’s position on that (Storm Shadow) specifically”.

She said: “We are providing military aid to support Ukraine’s clear right to self defence.”

She urged people to look at President Volodymyr Zelensky’s “own words, talking about the repeated attacks on Ukraine from Kursk, and as we say, we’re full of admiration for the ongoing bravery demonstrated by the Ukrainians in defending themselves from an illegal invasion”.