While recent drone sightings over airports in Germany and Denmark have triggered transport chaos, Poland shot down some of the small aircraft last month, and some were seen over UK airbases last year.

Countries across Europe have blamed Russia for the drone flights and agreed to boost military spending.

Russia, which launched its war on Ukraine in February 2022 spreading panic across Europe's eastern flank, denies being behind the drone flights.

The NATO military alliance said last week it was testing new anti-drone defences in eastern Europe to counter the threat from Russia.

"Russian aggression has escalated. It's extended even further into the West," Healey said in a speech at Mansion House in Central London.

"We will always do what's needed to defend British people, and as we speak, we are developing new legal powers to bring down unidentified drones over UK military bases."

Last year, unidentified drones were spotted over three airbases used by US forces in the UK -- RAF Lakenheath and RAF Mildenhall in Suffolk, and RAF Feltwell in Norfolk.

A joint military investigation between US and British forces was launched, but no information emerged about the origin of the devices.

The EU's foreign policy chief Kaja Kallas said Thursday that the bloc had no choice but to build up defences against Russian drones, as Brussels unveiled a "roadmap" to prepare for potential conflict by 2030.

"There is -- undeniably -- a new era of threat," Healey said.

"Not since the end of the Second World War has Europe's security been at such risk of state-on-state conflict."