Russian spies are plotting to cause mayhem on Britain’s streets, the boss of MI5 has warned

In a briefing in West London, Ken McCallum, director-general of MI5 warned: “If you take money from Iran, Russia or any other state to carry out illegal acts in the UK, you will bring the full weight of the national security apparatus down on you.'

Ken McCallum, director-general of the intelligence agency, said the UK should be braced for further attacks on home soil as the war in Ukraine continues. He added that MI5 had “one hell of a job on its hands” having foiled 20 Iran-backed plots in the last two years.

More than 750 Russian diplomats, many of them spies, have been expelled from Europe since Russia ’s 2022 invasion of Ukraine. This has led to Russia and Iran increasingly turning to British criminals and private intelligence officers to do their dirty work.

In a briefing at MI5’s counter-terrorism operations centre in West London, Mr McCallum warned: “If you take money from Iran, Russia or any other state to carry out illegal acts in the UK, you will bring the full weight of the national security apparatus down on you. It’s a choice you’ll regret.”

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Mr McCallum also revealed 43 terror plots in the UK have been smashed since 2017, and that a growing number of children are being investigated for far-right terrorism.

He said: “Sadly, 13 per cent of all those being investigated by MI5 for involvement in UK terrorism are under 18.

“That’s a threefold increase in the last three years. Extreme right-wing terrorism in particular skews heavily towards young people, driven by propaganda that shows a canny understanding of online culture.”

In a wide-ranging speech, the 50-year-old highlighted the threat from al-Qaeda and Islamic State, which he said had “resumed efforts to export terrorism”. And he said MI5 was “powerfully alive” to the risk tensions in the Middle East posed to the UK.

Mr McCallum said: “Ripples from conflict in that region will not necessarily arrive at our shores in a straightforward fashion; they will be filtered through online media and mixed with existing views and grievances.”

Three men are awaiting trial at the Old Bailey in connection with an alleged arson attack on a Ukrainian-owned firm in Leyton, East London, in March.

In 2018, two Russian nationals were suspected of using a nerve agent, Novichok, in a bid to kill double agent Sergei Skripal and his daughter, Yulia, in Salisbury, Wiltshire.