A BRIT tank crew took The Sun up close and personal with the mighty Challenger 2 tank on exercise near the border with Russia.
Some 14 of the incredible main battle tanks are due to be shipped to Ukraine as part of military aid to help them defeat Vladimir Putin.
The UK government is also sending some 30 A90 self-propelled artillery guns - which were also taking part in the exercises we were embedded with in Estonia.
Nato forces - including the UK - put troops through their paces in bitterly cold -12C conditions under the shadow cast by the war in Ukraine.
And as part of the drill, the heavy armour was wheeled out to show how it easily copes in the snow.
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Major Nick Bridges led us through a guided tour of the mighty Challenger 2, which weighs in at 64 tons and costs £4.2million.
"Much like a boxer in the ring, the Challenger 2 can take hits and continue to fight, whereas other tanks around the world might be knocked out after one round," said Major Bridges.
He went on: "The Challenger 2 was designed to meet the requirements of fighting the Warsaw Pact, based on the British Army's presence in Germany, so it's requirements are designed to meet a more defensive stance.
"Hence why it's not as fast as a Leopard tank, but it has a lot of additional armour."
Around 30 Challenger 2 battle tanks are currently in action as part of Nato's Winter Camp in Rakvere - just 80 miles from the border with Russia.
They are from armoured regiment the King’s Royal Hussars.
The impressive machines were deployed alongside other tanks, vehicles and troops from Estonia, France, Denmark and the US.
Maj Bridges explained the tank's steady ride on advanced suspension allows for more accurate shots from the main gun.
And he revealed its clever exhausts allow heat to be better dispersed around the tank, making them harder to detect with infrared cameras.
The 1,200bhp tank's 120mm cannon can be armed with armour piercing shells that fly towards the enemy at 4,250mph.
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It can also be armed with high explosive bunker busting shells that can blow up light enemy vehicles or entrenched positions.
The Challenger 2 can carry up to 1,800 litres of diesel, giving them an average 341 miles range at a speed of 37mph.
If needed, additional fuel can be sprayed on the hot engine to produce a smoke screen, providing cover for the tank.
The tank driver controls the vehicle with two sticks from an almost lying down position.
On each side are five smoke grenade dischargers, with can be fired as a smoke screen to the front, protecting against laser beam-riding missiles.
It also has a chain gun spitting out 7.62mm rounds to rip through soft-skinned vehicles such as trucks, or dismounted infantry.
Ukrainian soldiers are currently in the UK training how to use the Challenger 2s before they head to the battlefield against Russia.
Meanwhile, as Ukrainian soldiers begin training on Britain's beastly AS-90 self-propelled artillery weapons, The Sun has got up close and personal with these huge pieces of equipment.
Three of the weapons systems stand in a field in eastern Estonia, close to Tapa Camp, to be used during this year's Winter Camp.
Sergeant Cokely from the 19th Regiment of the Scottish Gunners, 127 Battery, shows us around one.
They can fire some 24.7km, and two rounds could flatten a building.
If needed, they can be ready to fire in just one minute.
Five personnel crew the artillery system, including the commander, the second in command who also drives the AS-90, two loaders who arm it, and one layer, who aims.
The loaders operate the power loading system, but if that goes down, they are able to load it manually.
While this is happening, the second in command is constantly scanning for threats to the rear of the vehicle.
It can fire high explosives, smoke rounds, and even anti-tank rounds.
The smoke rounds allow it to escape from trouble quickly, keeping the crew safe, as well as protecting one of the British Army's biggest assets.
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"If need be, I pop them, I hard reverse out and go," Sergeant Cokely says.
'WINGS FOR FREEDOM'
Troops were visited yesterday by Volodymyr Zelensky and Rishi Sunak at Lulworth Camp in Dorset.
Zelensky was making his first visit to the UK since the start of the war - and gave a rousing speech at Westminster.
The tightly controlled surprise visit came as he continues to call for more aid from the West.
And it comes amid the backdrop of a possible new Russian offensive later this month.
Zelensky called for the UK to send him fighter jets, urging MPs to give his forces "wings for freedom".
Sunak said "nothing is off the table" when it comes to the question of providing combat aircraft to Ukraine.
The Prime Minister added sending warplanes is "part of the conversation" about further aid to Kyiv.
Mr Zelensky warned that without supplies, including jets, ammunition and long-range missiles, there is a risk of "stagnation" in the conflict.
Downing Street confirmed that Mr Sunak has asked Defence Secretary Ben Wallace to investigate what jets the UK could potentially give.
Today Mr Wallace told the BBC there would be no immediate transfer of jets, and supplying them would take months.
He said it was "more realistic and more productive" to envisage the UK providing aircraft in the long-term to ensure Ukraine's security after the war has ended.
"This is not a simple case of towing an aircraft to the border," Mr Wallace told the BBC.
The UK also announced that it will start training Ukrainian air force pilots as part of a long-term strategy to safeguard Kyiv's future.
It marked a change in approach, with No 10 previously arguing that it would take too long to train pilots to fly Western fighter planes to have an impact on the war in eastern Europe.
The Russian Embassy in London warned the UK against supplying warplanes, saying Britain would bear responsibility "for another twist of escalation and the ensuing military-political consequences for the European continent and the entire world".
It warned: “Russia will know how to respond to any unfriendly actions by the British side."
The United States and other Nato allies have been wary of becoming more involved in the conflict for fear of provoking the Kremlin.
Mr Zelensky's trip to the UK included talks with Mr Sunak in Downing Street, a meeting with the King at Buckingham Palace, and a visit to Ukrainian armed forces in Dorset where they are being trained to use Challenger 2 tanks.
He then travelled to Paris to meet French President Emmanuel Macron and German Chancellor Olaf Scholz, telling a press conference there is "very little time" to provide the weaponry.
He he then went with Mr Macron to a gathering of EU leaders.
It is only his second trip abroad since Moscow's forces launched their full-scale invasion nearly a year ago.
Germany has pledged to send some of the brand-new Leopard 2 A7 tanks to Ukraine by April.
Described by a Brit soldier as "the most lethal tanks in Europe," The Sun Online saw them in action in Rakvere, eastern Estonia, as part of NATO's Winter Camp taking place this month.
The state-of-the-art German-built tanks are the newest of their kind, replacing the older A5s.
One British soldier told The Sun Online: "It has a 120mm gun firing NATO-standard ammo.
"It's probably most lethal tank in Europe."
Unlike the British-made Challenger 2 tanks which are heavier and mainly used for defence, the Leopard 2 A7 aims for maximum fire power and mobility.
However, if needed, it can be fitted with added armour to protect its crew.
It also comes with hunter-killer sites day and night.
This allows the gunner to engage the target while the commander can scan for a secondary target using a periscope.
This means that the only limitation is the speed of the loader, who can reload the gun in four to six seconds, according to the Brit soldier.
He added: "It can beat the Challenger in a drag race any day, but Challenger is bigger and heavier."
As the tanks break line in front of us, they take up positions on either side of the half-mile maze of trenches dug for the exercises.
This allows the infantry to move through the wood lines and take the trenches.
They take up a "hull down" position to protect themselves from attack, and can even take up a turret-down position for even more protection.
