The UK will send “armour piercing rounds which contain depleted uranium” to Ukraine, for use with the tank squadron donated by the British army.
Defence minister Baroness Goldie made the admission on Monday in response to a written parliamentary question from crossbench peer Lord Hylton.
Goldie said: “Such rounds are highly effective in defeating modern tanks and armoured vehicles.”
Russia has previously warned it would regard the use of depleted uranium in Ukraine as a ‘dirty bomb’.
Kremlin official Konstantin Gavrilov said in January: “If Kyiv is supplied with such shells for NATO heavy military equipment, we will consider this as the use of dirty nuclear bombs against Russia with all the ensuing consequences.”
Depleted uranium rounds have been linked to cancer and birth defects. They were fired extensively by allied forces in Iraq.
The rounds are radioactive and scientists believe their toxic effects on human health can continue to be felt long after conflicts have ended.
A White House spokesperson refused to confirm whether the US was supplying such rounds to Ukraine when asked by a reporter in January.
Britain is sending 14 Challenger 2 main battle tanks to Ukraine.