Ukrainian troops have arrived in the UK to begin training to use Challenger 2 tanks, the MOD has said.
Prime Minister Rishi Sunak has agreed to deliver a squadron of tanks to Ukraine to aid the country's efforts in re-taking territory lost to Russian forces.
Four British Army Challenger 2 main battle tanks will reportedly be sent to eastern Europe immediately, with eight more to follow shortly afterwards.
On Thursday, defence minister Alex Chalk told the House of Commons the UK would begin teaching Ukrainian soldiers how to use and fix the tanks "next week, on Monday".
He said the "intention" is for the Challenger 2s to arrive in Ukraine "at the end of March".
Before then, Mr Chalk said there will be a "really significant programme of training, not just for the tank crews who are to operate this vehicle but also for those who will be charged with maintaining it".
The US and Germany are also set to also deliver heavy tanks to Ukraine, with other countries such as France also not ruling out tank support, in what could be a pivotal move in Kyiv's war effort against Moscow.
Ukraine's President Volodymyr Zelensky has called for hundreds of tanks to help repel an expected spring offensive.
The expected deployment of Leopard 2s, Challenger 2s and the US's Abrams has been dismissed by Russia, which predicted they would "burn" on the battlefields of Ukraine.
Kremlin spokesman Dmitry Peskov said: "I am convinced that many specialists understand the absurdity of this idea.
"Simply because of technological aspects, this is a rather disastrous plan.
"The main thing is, this is a completely obvious overestimation of the potential (the supply of tanks) would add to the armed forces of Ukraine. It is yet another fallacy, a rather profound one," he added.