Experts wrote: “The People’s Republic of China (PRC) continues to provide critical support to Russia’s weapons production, including Oreshnik missiles and Shahed long-range drones.” Identified has been $10.3billion (£7.47bn) of technology and advanced equipment sent to the Kremlin by China during an unspecified time frame.

Russia is also understood to be using Chinese computer numerical control machines (CNC) to produce Oreshnik intermediate-range ballistic missiles (IRBMs) at the Votkinsk Plant in the Republic of Udmurtia, as well as to produce Shahed-type drones at the Alabuga Special Economic Zone (ASEZ) in Tatarstan.

China also supplies millions of dollars’ worth of microchips, memory boards, ball bearings, telescopic sights, and mounted piezoelectric crystals, The Telegraph found.

The ISW added: “The PRC continues to refrain from directly supplying Russia with weapons but is supplying components and equipment, many of which are dual-use, to the Russian DIB instead.

“ISW continues to assess that the PRC’s supplies to the Russian DIB have enabled Russia to improve and scale up its production of drones that Russian forces use to launch long-range strikes against the Ukrainian rear and to strike the Ukrainian near rear to generate battlefield air interdiction (BAI) effects along the front line.”

Sir Keir has taken a central role in the so-called “Coalition of the Willing”, a group of nations including Germany and France pledging support to Ukraine as it resists Vladimir Putin’s troops.

The Prime Minister is in China this week attempting to encourage investment in the UK from Beijing.

During their conversation, Downing Street said the pair “discussed the desperate situations many families face, including no heating or electricity, during freezing winter temperatures” amid Russia’s ongoing air strikes.

A Downing Street spokesperson added: “The President welcomed the UK’s announcement of £20 million in support for energy infrastructure earlier this month, which will strengthen Ukraine’s energy security amid escalating and indiscriminate Russian attacks on its critical infrastructure.

“The leaders discussed the progress made during recent peace talks in Abu Dhabi and agreed on the need for a just and lasting peace in Ukraine. The Prime Minister said that Ukraine has already shown its commitment to peace and that Russia must end the continued bloodshed.”