Under heavy grey skies and a thin coating of snow, hulking grey and green Cold War relics recall Ukraine’s Soviet past.

Missiles, launchers and transporters stand as monuments to an era when Ukraine played a key role in the Soviet Union’s nuclear weapons programme – its ultimate line of defence.

Under the partially raised concrete and steel lid of a silo, a vast intercontinental ballistic missile (ICBM) peeks out.

But the missile is a replica, cracked and mouldy. For almost 30 years, the silo has been full of rubble.

The whole sprawling base, near the central Ukrainian city of Pervomais’k, has long since turned into a museum.

As a newly independent Ukraine emerged from under Moscow’s shadow in the early 1990s, Kyiv turned its back on nuclear weapons.

But nearly three years after Russia’s full-scale invasion, and with no clear agreement among allies on how to guarantee Ukraine’s security when the war ends, many now feel that was a mistake.

Thirty years ago, on 5 December 1994, at a ceremony in Budapest, Ukraine joined Belarus and Kazakhstan in giving up their nuclear arsenals in return for security guarantees from the United States, the UK, France, China and Russia.

Strictly speaking, the missiles belonged to the Soviet Union, not to its newly independent former republics.

But a third of the USSR’s nuclear stockpile was located on Ukrainian soil, and handing over the weapons was a regarded as a significant moment, worthy of international recognition.

“The pledges on security assurances that [we] have given these three nations…underscore our commitment to the independence, the sovereignty and the territorial integrity of these states,” then US President Bill Clinton said in Budapest.

As a young graduate of a military academy in Kharkiv, Oleksandr Sushchenko arrived at Pervomais’k two years later, just as the process of decommissioning was getting under way.

He watched as the missiles were taken away and the silos blown up.

Now he’s back at the base as one of the museum’s curators.

Looking back after a decade of misery inflicted by Russia, which the international community has seemed unable or unwilling to prevent, he draws an inevitable conclusion.

“Seeing what’s happening now in Ukraine, my personal view is that it was a mistake to completely destroy all the nuclear weapons,” he says.

“But it was a political issue. The top leadership made the decision and we just carried out the orders.”

At the time, it all seemed to make perfect sense. No-one thought Russia would attack Ukraine within 20 years.

“We were naive, but also we trusted,” says Serhiy Komisarenko, who was serving as Ukraine’s ambassador to London in 1994.

“When Britain and United States and then France joined,” he says, “we were thinking that’s enough, you know. And Russia as well.”

For a poor country, just emerging from decades of Soviet rule, the idea of maintaining a ruinously expensive nuclear arsenal made little sense.

“Why use money to make nuclear weapons or keep them,” Komisarenko says, “if you can use it for industry, for prosperity?”

But the anniversary of the fateful 1994 agreement is now being used by Ukraine to make a point.

Appearing at the Nato foreign ministers’ meeting in Brussels this week, Ukraine’s Foreign Minister Andriy Sybiha brandished a green folder containing a copy of the Budapest Memorandum.

“This document failed to secure Ukrainian and transatlantic security,” he said. “We must avoid repeating such mistakes.”

A statement from his ministry called the Memorandum “a monument to short-sightedness in strategic security decision-making”.

The question now, for Ukraine and its allies, is to find some other way to guarantee the country’s security.

For President Volodymyr Zelensky, the answer has long been obvious.

“The best security guarantees for us are [with] Nato,” he repeated on Sunday.

“For us, Nato and the EU are non-negotiable.”

Despite Zelensky’s frequently passionate insistence that only membership of the Western alliance can ensure Ukraine’s survival against its large, rapacious neighbour, it’s clear Nato members remain divided on the issue.

In the face of objections from several members, the alliance has so far only said that Ukraine’s path to eventual membership is “irreversible”, without setting a timetable.

In the meantime, all the talk among Ukraine’s allies is of “peace through strength”. to ensure that Ukraine is in the strongest possible position ahead of possible peace negotiations, overseen by Donald Trump, some time next year.

“The stronger our military support to Ukraine is now, the stronger their hand will be at the negotiating table,” Nato Secretary General Mark Rutte said on Tuesday.

Unsure what Donald Trump’s approach to Ukraine will be, key providers of military assistance, including the US and Germany, are sending large new shipments of equipment to Ukraine before he takes office.

Looking further ahead, some in Ukraine are suggesting that a country serious about defending itself cannot rule out a return to nuclear weapons, particularly when its most important ally, the United States, may prove unreliable in the near future.

Last month, officials denied reports that a paper circulating in the Ministry of Defence had suggested a simple nuclear device could be developed in a matter of months.

It’s clearly not on the agenda now, but Alina Frolova, a former deputy defence minister, says the leak may not have been accidental.

“That’s obviously an option which is in discussion in Ukraine, among experts,” she says.

“In case we see that we have no support and we are losing this war and we need to protect our people… I believe it could be an option.”

It’s hard to see nuclear weapons returning any time soon to the snowy wastes outside Pervomais’k.

Just one of the base’s 30m-deep command silos remains intact, preserved much as it was when it was completed in 1979.

It’s a heavily fortified structure, built to withstand a nuclear attack, with heavy steel doors and subterranean tunnels connecting it to the rest of the base.

In a tiny, cramped control room at the bottom, accessible by an even more cramped lift, coded orders to launch intercontinental ballistic missiles would have been received, deciphered and acted upon.

Former missile technician Oleksandr Sushchenko shows how two operators would have turned the key and pressed the button (grey, not red), before playing a Hollywood-style video simulation of a massive, global nuclear exchange.

It’s faintly comic, but also deeply sobering.

Getting rid of the largest ICBMs, Oleksandr says, clearly made sense. In the mid-1990s, America was no longer the enemy.

But Ukraine’s nuclear arsenal included a variety of tactical weapons, with ranges between 100 and 1,000km.

“As it turned out, the enemy was much closer,” Oleksandr says.

“We could have kept a few dozen tactical warheads. That would have guaranteed security for our country.”