The United States has banned Britain from sharing intelligence from Washington with Ukraine as part of its withdrawal of support for Volodymyr Zelensky.

Donald Trump's decision to freeze American military aid to Kyiv yesterday brought warnings that Ukraine could run out of weapons in as little as two to three months' time.

But on top of missiles and ammunition, all UK intelligence agencies and military outlets also received an order expressly forbidding the sharing of US-generated intelligence, previously known as 'Rel UKR' - short for Releasable to Ukraine'.

Since the conflict began three years ago, the UK and other Western security partners such as Australia and New Zealand have shared such knowledge with Ukraine.

But the Mail has learnt the top-level security classification has now been removed by the United States pending further notification and is likely to impact upon Kyiv's ability to defend itself against Russia's continuing onslaught.

The ban affects the likes of the UK's GCHQ, the spy agencies and intelligence branches of the Ministry of Defence.

Last night, UK military intelligence expert Phil Ingram told the Mail: 'The United States's instruction to stop allies sharing US-derived intelligence with Ukraine is what I would expect.

'The US's intelligence partners, including Britain, have had their authority to pass on intelligence revoked.

'The US will tightly control distribution of its intelligence to Ukraine through agencies based in Kyiv.'

The move coincided with the US confirming it was pausing military aid to Kyiv as the rift between the two supposed allies deepened before Ukraine's president Volodmyr Zelensky offered US counterpart Donald Trump an olive branch yesterday.

Last night, a senior Ukrainian official told the Financial Times: 'We have two to three months. After that, the position will be very difficult for us.

'It will not be a total collapse, but we will be forced to withdraw from some areas more quickly'.

Critics suggested any long-term freeze would lengthen rather than shorten the war.

That is because it is expected to encourage the Kremlin to exploit Kyiv's dwindling weapons and ammunition stocks and launch a fresh bid for more territory.

Russia currently occupies around one fifth of Ukraine, including eastern provinces and the Crimean peninsula.

Ukraine is clinging on to a relatively small amount of territory it seized last year in the southern Russia province of Kursk.

Currently, Ukrainian and Russia troops are facing off along a 600-mile frontline, which has gradually been pushed deeper into Ukraine due to Russian advances.

The decision to suspend military aid came three days after a dramatic clash in the Oval Office between presidents Trump and Zelensky.

To date, the US has provided military aid worth £53 billion to Ukraine, compared to Europe's combined total, which includes Britain, of £51 billion.

While, in theory, Europe could eventually double its support for Ukraine - and use frozen Russian assets to pay for weapons - the US supplies a lot of high-end equipment that other states do not possess.

The impact of the suspension of military aid could be felt first by Ukrainian civilians should US-gifted Patriot defence missile systems run dry and leave Kyiv unable to protect its skies from Russian bombardments.

Last night, Nato allies expressed regret over the decision. Finnish Foreign Minister Elina Valtonen told a thinktank in London 'we need the Americans militarily.

'This definitely shouldn't be a moment where we give in. As on the battlefield, Russia has not really been advancing in recent months.'

French prime minister François Bayrou said the freeze on aid was akin to abandoning Ukraine in favour of a Russian victory.

He told French senators: 'The word 'suspension' fools no one.