The United Kingdom might be supplying Ukraine with Challenger 2, the British Army's main tank, and there have been talks about the affair for the past two weeks, a source familiar with the matter said, as per Sky News.

The authorities in Downing Street still have not made a final decision, but if the United Kingdom fulfills the requests of the Ukrainian authorities, this would make London the first western power to have responded to Kiev's demands to be supplied with key tanks from the West. This could be a domino effect that would lead other NATO allies to supply Ukraine with tanks.

The Contact Group, a US-led mechanism of 50 nations pumping arms into Ukraine, is set on holding its next meeting on January 20. This upcoming meeting could see London announcing the support in the form of tanks that it is intending to send to Ukraine.

This aid package could include around 10 Challenger 2 tanks, which would be enough to arm an entire squadron, one source told Sky News.

The same source admitted that this would not necessarily tip the balance of power, but it would make for a first in terms of Ukraine receiving Western tanks, opening up the opportunity for many other nations to do so after the collective West saw this as a move that Russia would perceive as greatly escalatory.

This comes days after the Pentagon announced that the latest military assistance package for Ukraine worth $3.75 billion includes 50 Bradley fighting vehicles, 500 TOW anti-tank missiles, and 250,000 rounds of 22mm ammunition.

According to US Deputy Assistant Secretary of Defense for Russia, Ukraine, and Eurasian Affairs Laura Cooper, it will take a couple of months to field Bradley fighting vehicles in Ukraine.

It will also include 100 M113 Armored Personel Carriers, 55 Mine Resistant Ambush Protected Vehicles (MRAPs), and 13 High Mobility Multipurpose Wheeled Vehicles (HMMWVs), in addition to 70,000 155mm artillery rounds, 500 precision-guided 155mm artillery rounds, and 1,200 155mm artillery rounds of the Remote Anti-Armor Mine (RAAM) system. 

The package additionally provides Ukraine with 36 105mm towed Howitzers and 95,000 105mm artillery rounds, 10,000 120mm mortar rounds, additional ammunition for HIMARS, and approximately 2,000 anti-armor rockets. 

Ukraine is still waiting for Germany to change its mind on the issue, hoping for its Leopard II tanks to end up on the eastern front.

Late last year,  The Telegraph newspaper reported that the United Kingdom intended to increase defense spending by around 1.5 billion pounds ($1.8 billion) in light of the Ukraine war. UK Chancellor of the Exchequer Jeremy Hunt is expected to announce the increase for the fiscal year 2025 in the spring of 2023.

In late November, British Prime Minister Rishi Sunak vowed that his country would stand by Kiev's side "until Ukraine has won" during his first visit to the Ukrainian capital since taking office.