The threat of a Russian hybrid attack on the UK is rising, officials and experts fear, after the use of an explosive drone to target a German airport marked a further escalation in tactics deployed against countries supporting Ukraine.

The German government took the unusual step of attributing the attack at Leipzig/Halle Airport directly to Russia on Tuesday, saying the explosives and equipment used had been seen in “other hybrid operations of Russia and its war against Ukraine”.

Britain sees the Russian escalation of grey zone activity, including the attempted attack on Leipzig airport last month, as “serious”, but not out of character from Putin, government sources have said.The UK is understood to be working closely with the German government on countering Moscow’s hybrid warfare.

While there is not expected to be any specific response from the British government to the Leipzig incident, including joining the EU in imposing fresh sanctions on Russia, Downing Street said the UK “stands in full solidarity with Germany following Russia’s reckless attack in Leipzig, and as the Prime Minister made clear, Russian attempts to undermine our support for Ukraine are futile and doomed to fail”.