The war in Ukraine has reached a stalemate, but the battle balance may be set to shift after Britain announced it will send Kyiv the Western-made heavy tanks it has long been calling for.
Western leaders have been treading carefully, continuously resisting pleas from Ukrainian President Volodymyr Zelenskyy for more powerful battle tanks, which will help push back Russia's invasion.
The UK has now delivered a concrete pledge, announcing over the weekend it would send 14 Challenger 2 tanks.
There is optimism more NATO countries will follow suit and start "upping the ante" in the types of weapons they are willing to provide, Matthew Sussex, a senior fellow at the ANU's the Centre for Defence, told the ABC.
Germany is also expected to succumb to pressure to authorise the export of its Leopard 2 tanks, which are considered one of the best in the West.
"There's been a lot of reticence amongst West European countries about sending tanks to Ukraine," Professor Sussex said.
"This decision by the UK is probably something that Ukrainians hope starts a bit of a domino effect."
There were already signs heftier ground support would soon be rolling in from European allies.
NATO Secretary General Jens Stoltenberg told German media on Sunday that the war was in a decisive phase, and it was important to provide Ukraine with the weapons it needs to succeed.
The comments came amid renewed missile attacks by Moscow targeting multiple Ukrainian cities.
A multi-story residential building, where officials said about 1,700 people lived, was struck in the south-eastern Ukrainian city of Dnipro on Saturday, killing at least 30 people.
Why tanks now?
In recent months, the range of weapons being provided to Ukraine has been expanding.
In particular, the West has been beefing up Kyiv's air defence capabilities, sending sophisticated systems such as NASAMS and the IRIS-T.
A new milestone was reached in late December when the US finally agreed to send its most advanced air defence system — the in-demand Patriot.
But as the war becomes static and battlelines barely shift, Russia has been taking aim at Ukraine's civilian infrastructure.
President Zelenskyy has said the Russian "terror" could be stopped only on the battlefield.
"The war is at a bit of a stalemate, and if Ukraine is going to have any chance of expelling the Russians from its territory, then it's going to need more offensive weaponry," Professor Sussex said.
"Tanks are pretty critical to that."
Ukraine's European allies have sent Kyiv more than 300 modernised Soviet tanks since Russia invaded in February 2022.
And earlier this month, France, Germany and the United States respectively promised French AMX-10 RC light tanks, 40 German Marder infantry vehicles, and 50 Bradley fighting vehicles.
What sets main battle tanks such as the Challenger 2 apart is their larger guns and more effective armour-piercing shells.
"If you have enough of those, you can blow reasonably-sized holes in enemy lines, and then you can advance with people on foot and in things like Bushmasters," Professor Sussex said.
Vasyl Myroshnychenko, the Ambassador of Ukraine to Australia, told ABC's RN Breakfast that the tanks provide additional armour and fighting capability Ukraine needs to win the war.
"To win this war we need the right weapons to drive the Russians out of Ukraine," he said.
"Tanks are used for offensive [measures], and we need to go counteroffensive on the Russians to be able to expel them from Ukraine."
Australia has been providing Bushmaster armoured vehicles to Ukraine, which Mr Myroshnychenko said Kyiv was thankful for.
But he said they were "discussing different options" with the Australian government to provide further support.
"We have been very thankful to Australia for the APCs [Armoured Personnel Carriers] as well as for the armoured personnel vehicles, such as Bushmasters," he said.
"However, in order for us to advance and to be able to kick Russians out of Ukraine, we need a different armour."
Why are countries resisting?
Countries like Germany have argued that sending equipment like tanks, which are offensive weapons, risks drawing the West further into the conflict.
There were also concerns such moves could be seen as an escalation.
Britain's pledge over the weekend drew a swift reaction from Russia, which warned it would only "intensify" the conflict.
"Bringing tanks to the conflict zone, far from drawing the hostilities to a close, will only serve to intensify combat operations, generating more casualties, including among the civilian population," the Russian embassy in the UK said.
Moscow has condemned escalations in arms supplies for Ukraine in the past, but it has not led to any military consequences for the West.
Professor Sussex said the decision to send tanks is "pretty prudent" compared to actions that could have been taken.
"I don't see it as an escalation so much," he said.
"I think it is a sort of doubling down and a sign that they're not prepared to allow Putin to get away with seizing large amounts of Ukrainian land."
Mr Myroshnychenko said at this point "there's no other option".
"If Ukraine is going to lose this war, the implications for the Western world and Australia included will be devastating," he said.
He believes the UK's move is a "turning point in supplies" and hopes it will lead to Berlin approving countries such as Poland and Finland to send the German-made Leopard 2 tanks.
A decision is expected to be made when Western defence ministers meet later this week.
