Four men were arrested in London yesterday as part of an investigation into Islamist-related terrorism. At least one of the men is suspected of having a connection to Isis.
Whitehall officials said last night that the arrests “may have foiled the early stages” of a plan to attack the UK.
The men were held in a series of dawn raids, and one of the suspects was tasered.
The four men, aged between 20 and 21, were arrested on suspicion of being involved in the commission, preparation or instigation of terrorism.
The arrests came amid a heightened alert, with fears that jihadists returning from Syria could pose a threat to Britain.
The Metropolitan Police Commissioner Sir Bernard Hogan-Howe told BBC London Radio: “It is difficult to talk in a great deal of detail about it, but it is a quite serious case.
“It is one of a series of arrests that we have had over the last few weeks which taken together for me confirm that the drum beat around terrorism has changed.
“It’s a more intense drumbeat – we are having to be more interventionist and a lot of it is linked back to Syria and Iraq. These are arrests that in some way or other have got that sort of link.” He added: “I don’t want to worry the people of London – we are here to keep them safe and we believe we are on top of things – but there are some concerns about the people we are having to arrest.”
There have been warnings that British foreign policy could have repercussions at home after the RAF joined a US-led coalition in the bombing of Isis targets in Iraq.
Last night it was reported that the security service MI5 and counter-terrorism officers used surveillance to assess that one of the men may have access to weapons. That discovery contributed to the decision to send armed officers to one of the addresses raided from Scotland Yard’s specialist firearms unit SCO19. It was at that address that the Taser was fired. The four men arrested were all resident in Britain.
Whitehall sources said that officers believe the raids were an “early disruption” of what could have been a “significant plot”.
A Scotland Yard statement said: “These arrests and searches are part of an ongoing investigation into Islamist-related terrorism.”
All the men were arrested on suspicion of being concerned in the commission, preparation or instigation of acts of terrorism and have been taken to police stations in central London and remain in custody.