Hidden in the thick woodland between Kharkiv and the Russian border, three men in black overalls clambered over a heavily camouflaged tank.

Andrei Tonko, a wiry 53-year-old in command, hopped down and watched critically while his driver gunned the engine.

The machine rose like an animal waking up, hauling itself out of its conceal ditch and pirouetting in the mud with an unlikely grace.

“It’s the most difficult job in the whole damn war,” he said when the roar of the engine had died and the pall of white exhaust fumes began to disperse.

“I’m not saying the infantry have it easy – they have their own problems,” he said. “But if you’re in a tank, you are the first target the enemy looks for. The moment they spot you, you’re under fire – mortars, artillery, rockets."

Counterfire, he and his crew explained, comes quickly. In combat, you can get off a maximum of 10 shots before the driver stamps on the reverse gear and drives away as fast and as far as possible. A moment's hesitation can be fatal.

The Ukrainian countryside is by now thickly sown with powerful anti-tank mines, but “if you stay still, you’re dead”, said Andrei. “Scary? Of course it is scary. But I have the best crew. Everyone is scared, but everyone does their job."

It is a crucial job.

The disastrous failure of Russia’s armoured assault on Kyiv early in the war prompted some military experts to write obituaries for the tank.

But Ukraine’s counter offensive in the Kharkiv region has proven that tanks – when properly used with supporting infantry and air cover – remain crucial to offensive manoeuvre warfare.

Massed “tank fists” helped the breakthrough that led to the collapse of Russia’s Izyum army grouping earlier this month. Mr Tonko and his comrades rode in a simultaneous assault that chased the Russians across the border just a dozen kilometres to the north of this spot

If Ukraine is to continue to press the offensive, it needs more of them. But Western countries have proven mysteriously reluctant to provide them.

Germany, which produces the Leopard, the Nato tank best suited to Ukraine's needs, has ignored Kyiv. The Americans recently hinted that tanks may be "on the table" but have not provided any.

In recent weeks Ukrainian officials have taken to raising the issue in public almost daily in the hope of changing minds.

“The best response and security investment – tanks for Ukraine. Especially German ones…” Mykhailo Podolyak, an adviser to Volodymyr Zelensky, wrote on Wednesday after the sabotage of the Nord Stream gas pipelines.

In the meantime, the Ukrainians are relying on old Soviet models. Tonko’s is an elderly T64BV. He and his crew were told it was captured from the Russians when they were given the keys.

The crew say they are fond of it. “It depends what you’re used to. Some people are used to the 72. We are used to the 64,” said Tonko

But there is no concealing this weapon's age. The T-72, a more modern Soviet tank, is bigger and "basically better, the engine, the optics," he admits. Asked if the metal bricks of explosive reactive armour actually worked, he pulled a face. “This stuff was good in the 1970s,” he said. “There are modern versions but we don’t have them.”

The crew are younger than the tank but hardly what would be called fighting age in a professional army.

We can guess – either they will move in the direction of Kharkiv in the second echelon or towards Donetsk, but I don’t know yet. When they start to move and line up in battle formation, we will understand where they are going.”

Many Western analysts suggested it would take two to three months for conscripts to reach the battlefield because they needed to be trained, equipped, and integrated into their units.

But reports from Russia suggest many have been dispatched to front-line units with as little as one day’s training.