Russia says the UK’s decision to share missile blueprints with Ukraine is evidence of its direct military involvement in the war.

Factories manufacturing drones in the United Kingdom for export to Ukraine could come under attack from “unknown sources”, a Kremlin adviser has said, after Britain agreed to share long-range missile blueprints with Kyiv.

Andrei Fedorov, an adviser to the Kremlin and a former deputy foreign minister, told British broadcaster BBC on Tuesday that he could not “exclude 100 percent” that there might be some “semi-military” action against Britain, as UK Prime Minister Andy Burnham visited Ukraine.

The UK shared missile blueprints with Ukraine for it to manufacture French-British designed long-missile drones during Burnham’s first overseas trip to Kyiv on Monday. Sharing these blueprints, according to the Russian adviser, is seen by Moscow as proof of the UK’s “direct military involvement” in the Russia-Ukraine war.

Fedorov said that “sooner or later, there might be not only verbal but maybe some visible reaction from Russia towards the UK”.

Asked to elaborate, he said: “There are different discussions how it should look like – it might be so-called technical reaction, maybe some hackers attack from unknown source, not from official level, of course.”

“There might be different political steps, and I cannot exclude 100 percent that there might be some semi-military.”

“For example, something might happen with enterprises, with the factories which are producing drones for Ukraine, etc.”

Kremlin spokesman Dmitry Peskov shared similar sentiments with reporters on Monday, stating that the UK is “participating in this war” by its missile support and that this is adding “fuel to the fire”.

Burnham responded in Kyiv by asking reporters who started the fire in the first place. Russia launched its full-scale invasion of Ukraine in February 2022.

The UK has agreed to declassify blueprints for British-made components for the Scalp missile, a French-produced version of the Storm Shadow that has already been used to hit targets in Russia.

The Scalp missile can hit targets that are heavily fortified, such as bunkers, unlike existing Ukrainian missiles. It has a range of about 240km (149 miles).

Ukraine has increased its production of cheaper drones significantly in the past year, attacking more economic and military targets within Russia.