Iran has raised the stakes in its sabotage efforts against military bases in the UK with Tehran behind multiple plots, the head of the UK's domestic intelligence service warned.
Authorities have arrested scores of people suspected of working for Iran, as the level of state-backed threats against the UK exceeds terrorism and extremist activity, Ken McCallum, the director general of MI5, revealed on Tuesday.
“Over the last 12 months, our Iran-linked operations have led to more than 50 arrests in the UK,” he said. “The other major shift this year has been Iranian ambitions to come at harder targets, like military sites.”
British Prime Minister Andy Burnham said Tehran was "highly likely" behind a suspected plot against RAF Fairford on Monday.
The base had been used by US bombers to carry out strikes on Iran since the war was launched in February. The plot prompted a security alert and led to US President Donald Trump withdrawing planes from the air base. Seven people have been arrested on suspicion of involvement in the incident.
Two more suspects were arrested last week at the RAF Molesworth base in Cambridgeshire, which is known to be used by US intelligence agencies.
Mr McCallum warned an even greater threat existed elsewhere, raising the prospect of more "aggressive and sophisticated" tactics spreading to the UK.
"Clearly it is the case that in countries closer to its own homeland, the IRGC [Islamic Revolutionary Guard Corps] has quite deep experience of using more conventional and hybrid technology," he said.
Iran has previously attempted attacks at UK bases in Diego Garcia in the Indian Ocean and Akrotiri in Cyprus.
The UK has prosecuted dozens of people for carrying out attacks on Jewish sites and on dissidents active in London and other parts of the UK. Mr McCallum's last national security update a year ago revealed that there were 15 active plots disrupted within the UK.
In his latest his annual report he added that all state threats, including from Russia and China, had quadrupled.
He referred to interconnected financial systems, energy grids, supply chains and manufacturing bases – designed during simpler times for maximum efficiency – as key vulnerabilities to disruption and coercion by foreign actors.
EU support
Kaja Kallas, the EU's foreign affairs minister, expressed solidarity with the British government on Tuesday, following Mr Burnham's statement.
"UK has now concluded that Iran’s Revolutionary Guard was almost certainly behind the threat to Fairford airbase," she said. "Iran’s campaign of intimidation and chaos extends well beyond the Middle East.
"The EU has already designated the Revolutionary Guard as a terrorist organisation. We have sanctioned Iranian officials for undermining freedom of navigation and serious human rights violations. The UK is a close partner, and we stand firmly with them."