Ukraine’s relationship with the UK has “got worse” since the Labour government took power in July, officials in Kyiv have told the Guardian, voicing frustration over Britain’s failure to supply additional long-range missiles.

The UK prime minister is yet to visit Ukraine four months after taking office and a frustrated Kyiv has said that a trip would be worthless unless Keir Starmer committed to replenishing stocks of the sought-after long-range Storm Shadow system.

“There’s no point in his coming as a tourist,” one senior figure in Volodymyr Zelenskyy’s administration said at a time when Ukraine is acutely concerned about the impact that Donald Trump’s US election victory will have on its war effort.

Ukraine is growing increasingly unhappy with London as Russian troops advance in the east of the country at their fastest rate since 2022, with US officials concluding that the frontlines can no longer be considered static. Ukrainian commanders said they were heavily outgunned.

At the same time, Trump’s election victory on Wednesday has raised concerns that the US could halt or slow military aid to Ukraine and force Kyiv to negotiate a humiliating peace with Russia.

Ukraine’s principal complaint with the UK is that it has not supplied any additional missiles from its reserves of Storm Shadow, even for use against targets in Crimea and other Ukrainian territories occupied by Russia since 2014.

The official said: “It isn’t happening. Starmer isn’t giving us long-range weapons. The situation is not the same as when Rishi Sunak was prime minister. The relationship has got worse.”

Sunak visited Kyiv in November 2022 within a month of becoming prime minister. Boris Johnson, his predecessor but one, enjoyed a close relationship with Zelenskyy and was considered by Ukraine a critical source of support shortly after Russia launched its full-scale invasion in February 2022.

Storm Shadow is a highly accurate cruise missile with a range of about 155 miles developed via an Anglo-French collaboration. Stocks are also held by Italy. Though expensive, at $1m (£800,000) a time, it is considered effective against static targets and has been used to strike at Russian naval assets in Crimea.

Britain and France said in 2023 they would supply Storm Shadow missiles, known by the French as Scalp, but the number of strikes has dwindled during 2024. “You would know if the UK had provided us with new Storm Shadow missiles because we would be using them to hit Russian targets. We are not,” the official added.

The last Storm Shadow strike claimed by the Ukrainian military was on 5 October, targeting Russian command posts. Prior to that five or more missiles were thought to have been used against Sevastopol naval base in March of this year.

Starmer met Zelenskyy on Thursday at a European political summit in Budapest. The prime minister said the UK’s support for Ukraine was “unwavering” and acknowledged “we need to step up”. “It’s very important that we stand with you,” Starmer said.

But the Ukrainian president pointed to the private frustrations in a social media post, accompanied by a picture of the two leaders. “An important element of the victory plan is providing Ukraine with long-range weaponry and granting permission to use it against military targets on Russian territory,” Zelenskyy said.

Privately, sources in Kyiv complained that the meeting in Hungary led to “no progress at all” on the missile issue. Until deliveries of Storm Shadow resumed there was little point in Starmer travelling to Kyiv, they added.

“We have been discussing since August a possible visit by Starmer. Various dates have come and gone. Starmer has postponed several times,” the official said. They added: “There’s no point in his coming as a tourist. At the moment he’s not willing to take the decisions which are necessary.”

Downing Street said that the UK’s “support for Ukraine is ironclad” and that Starmer has been clear that his government would stand with Ukraine for as long as it took, emphasising the number of meetings between the two leaders since Labour took power in July.

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A No 10 spokesperson said: “One of the prime minister’s first decisions in office was to commit to spending £3bn on support for Ukraine every year – since then, the prime minister has met President Zelenskyy six times, including hosting him at No 10 twice, and meeting him at the European political community meeting in Hungary this week.”

Britain is the third-largest donor of military equipment after the US and Germany. The total committed by the UK since 2022 has been £12.8bn, of which £5bn is financial and humanitarian support and £7.8bn is military aid.

On Friday, Starmer appointed Tony Blair’s chief of staff Jonathan Powell as national security adviser. Powell has long advocated negotiating with enemies to bring about peace, prompting one Ukraine expert and Labour historian to argue that he might add to pressure on Kyiv to negotiate a truce with Russia. Brian Brivati, a former director of the John Smith Trust, said: “Of course there has to be a deal at some point, but for Trump and Powell it is the end of fighting that counts, which is not the same as peace.”

The outgoing Biden administration has $6bn remaining of unallocated security assistance, enough to help Ukraine through 2025, but it is unclear if it can get the exports together quickly enough before Trump takes over in January.

Zelenskyy has also repeatedly urged the UK to lift restrictions on the use of Storm Shadows against military sites deep inside Russia. Downing Street had been thought to be sympathetic to the request but has not rescinded the ban because of entrenched opposition from the Biden administration.

Disillusionment on the Ukrainian side with the new government follows discussions between Starmer and Zelenskyy last month at No 10. Zelenskyy presented his “victory plan”, which includes Nato membership for Ukraine, and more military and economic support from key allies.

The plan met “no big response”, the senior official said. They suggested that Starmer was unwilling to make strategic decisions without approval from Washington, despite private assurances he made to Zelenskyy that the UK had freedom to act independently.

In recent months the Kremlin has stepped up bombardments using Iranian Shahed and ballistic missiles, with a major drone attack early on Thursday. Much of Ukraine’s energy infrastructure has already been destroyed as the freezing winter season approaches, and air raid alerts in Kyiv and other cities sound practically every night.

Meanwhile, as many as 10,000 North Korean soldiers are mustering in western Russia to join battle against Ukraine. In a post last week on X, Zelenskyy accused the US, UK and Germany of passively “watching” as North Korea’s army took part in a war in Europe. He urged allies to approve long-range strikes so that North Korean troops might be attacked before they killed Ukrainians.