Britain will deploy the high-tech Sky Sabre missile defence system and around 100 personnel to Poland, No.10 has said.
Boris Johnson’s spokesperson said the equipment and troops had been requested by the Polish government.
“It is, as ever, a purely defensive capability which we are providing on a bilateral basis to Poland,” the spokesperson said.
Downing Street said the weapons would “remain under UK control at all times” and was a “short-term deployment”.
According to the Ministry of Defence,Sky Sabre is capable of intercepting 24 objects the size of a tennis ball travelling at the speed of sound at the same time.
Earlier this week it was reported a Russian drone flew over Poland’s airspace before entering Ukraine, where it was shot down by Ukraine’s military.
It comes as the UK joined five other nations calling for a United Nations Security Council meeting on Ukraine on Thursday.
On Friday a vote is expected on a resolution demanding protection for Ukrainian civilians “in vulnerable situations”.
“Russia is committing war crimes and targeting civilians,” the UK’s UN mission tweeted, announcing its joint plea alongside the US, France and others.