The UK will likely come under direct attack from Russia, with four weapons manufacturing locations under serious threat, according to security experts. Colonel Richard Kemp, the former government terrorism adviser, has warned of a “direct threat against ordinary British people” as the Kremlin targets UK companies that make weaponry for Ukraine.

It comes after the UK government accused Vladimir Putin of carrying out an operation to survey and tamper with underwater cables and pipelines around the British Isles. Although the Kremlin has denied the accusations, Defence Secretary John Healey told the Russian President that “we see you” and “your activity over our cables and our pipelines”. Colonel Kemp is now urging the Government to take Russian intelligence threats seriously, highlighting the risk against British weapon manufacturers.

He told the Mirror: “We should expect sabotage attacks launched by Russia but in such a way that they are deniable operations because the UK is seen as vulnerable. This is a direct threat against ordinary British people, workers at these places which will have some security but which will be seen as vulnerable as it will not be enough.

“I would see these operations as probably being launched by criminal organisations linked to Russia and the threat should be taken extremely seriously.

“In my view the Kremlin is very likely to arrange for an attack such as this because they believe that they would get away with it and will be aimed at intimidation. They certainly have the capability and have shown that they are willing to do this before, without sacrificing their own agents.”

Meanwhile, security sources told the publication that it is “very possible” that Russia has deep-cover sleeper agents across the UK. However, according to Colonel Kemp, they are “unlikely to sacrifice or risk their own agents on something like this”.

The UK has announced its biggest ever drone package for Ukraine, including over 120,000 long-range strike drones, intelligence and reconnaissance drones, logistics drones and maritime capabilities. The government said they are “critical” to both Ukrainian counterattacks as well as their defence against continued Russian attacks.

Russia continues to bombard Ukraine with missile and drone strikes. At least 16 people were killed in overnight attacks across the nation, with a wartime record number of drones hitting Ukraine in March.

Russian defence chiefs have accused Ukraine of drawing other countries into the conflict. Addresses in London, Leicester, Reading and a key US air base have been named as potential targets.

The Russian defence ministry said: “The leadership of several European countries, amid mounting losses and a worsening shortage of manpower in the Ukrainian Armed Forces, decided to increase the production and supply of UAVs to Ukraine for strikes on Russian territory.

“A significant increase in UAV production for the Kyiv regime is planned through increased funding for Ukrainian and joint enterprises located in European countries that produce attack drones and their components.”

Dmitry Medvedev, a senior Kremlin official, has warned Western leaders that the threat should be “taken literally”. He said: “The list of European facilities which make drones and other equipment is a list of potential targets for the Russian armed forces.When strikes become a reality depends on what comes next. Sleep well, European partners!”

Manufacturing facilities in Germany, the Netherlands, Latvia, Lithuania, Poland, the Czech Republic, Spain, Italy, Israel and Turkey have also been named as potential Russian targets. According to the Centre for Strategic and International Studies, Russia remains in an “aggressive campaign of subversion and sabotage against European and U.S. targets, which complement Russia’s brutal conventional war in Ukraine”.

Putin fired a total of 31 missiles and 636 drones into Ukraine overnight. Targets were struck in Kyiv, Dnipro, Odesa and Kharkiv with at least 16 dead.