"London's actions will inevitably have consequences for which it will be held accountable," the Russian embassy in the UK wrote.
The statement comes after The Sunday Times reported that drones from British companies were used by Ukraine to strike targets in Russia.
Russia has repeatedly issued warnings and threats against countries that have supported Ukraine in various ways during the years of Russia's war of aggression.
Ukraine has in recent months escalated its long-range attacks on targets in Russia. At the same time, Moscow has intensified its missile and drone attacks on, among other things, the Ukrainian capital, Kyiv.
