Britain has been hit by an “unprecedented” wave of terror attacks and one atrocity may be triggering the next, the country’s top police officer has warned.
Scotland Yard chief Cressida Dick said authorities were confronting a “new reality” after three deadly assaults hit the UK in just 10 weeks.
In the latest outrage, three terrorists killed seven victims and injured dozens more in the London Bridge area on Saturday night.
The attackers, who were wearing fake suicide bomb vests, were shot dead by eight officers after police opened fire with a hail of 50 bullets.
The incident followed murderous strikes in Westminster and Manchester in March and May, and Ms Dick, whose policing career spans more than 30 years, said the flurry of attacks was “unprecedented in my working life”.
The Islamic State terror group - also known as Daesh - has claimed responsibility for the London Bridge rampage, while the attack has sparked fears Britain is in the grip of a spate of copycat incidents.
Ms Dick told BBC Radio 4’s Today programme that it was “certainly a possibility” that the attacks were triggering the next one.
“The rhetoric that has been coming from Daesh and other organisations has been to encourage people to take action into their own hands, to use low-tech methods, and undoubtedly when people see something which appears from their perverted point of view to be successful, some people will be inspired by that, so that is most certainly a possibility,” the Metropolitan Police commissioner said.
As counter-terrorism police units and security services launched a huge investigation for the third time in a matter of weeks:
:: Eleven people arrested on Sunday remained in custody.
:: Two further addresses in east London were searched on Monday morning, with a number of people detained.
:: Ms Dick confirmed police knew the identity of all three killers and Scotland Yard said it will release their names “as soon as operationally possible”.
:: A friend of one of the perpetrators told the BBC Asian Network he had reported him to the anti-terror hotline after he began expressing increasingly radical views and justifying terror attacks, but the man said he was never arrested.
:: Security sources in Dublin said one of the terrorists was carrying an identity card issued in Ireland when he was shot dead.
:: The first victim of the attack has been named as Canadian national Christine Archibald, who worked in a homeless shelter until she moved to Europe to be with her fiance.
:: Theresa May defended cuts to police numbers, insisting the Metropolitan Police is “well resourced” and has “very powerful counter-terrorism capabilities”.
Hundreds cowered in pubs and restaurants, barricading themselves inside as the attackers stalked the streets as terror hit Britain less than a fortnight after the Manchester bombing.
Pedestrians were struck by a van on London Bridge before attackers stabbed a police officer and revellers around Borough Market with 12in knives.
One of the attackers shouted “this is for Allah” as he knifed a man near a pub, before the trio were shot dead by armed officers within eight minutes of police receiving the first emergency call.
Tales of heroism emerged, with one British Transport Police officer taking on the attackers armed only with his baton before being stabbed in the head, face and leg.
Three other officers were hurt in the attack. In total, 48 people were injured, with 21 in a critical condition.
Mrs May said victims of the attacks came from “number of nationalities”, adding: “This was an attack on London and the United Kingdom, but it was also an attack on the free world.”
A large-scale probe has been launched, with detectives amassing an enormous amount of forensic material during a string of searches around east London.
Seven women and five men aged between 19 and 60 were arrested under the Terrorism Act in Barking on Sunday. A 55-year-old man was later released without charge.
Residents reported hearing loud bangs on Monday morning as two further properties were searched.
Scotland Yard said officers entered two addresses - one in Newham and another in Barking.
The force said: “A number of people have been detained and are at present being spoken to. Searches are ongoing at both addresses.”
Police vans were parked outside a property on the A13 in Dagenham.
James Bateman, who lives at the other side of the road, said: “At about 4am, after the large bang, I looked outside the window after being woken up and I saw about a dozen armed police officers going to and from an unmarked van.”
He said they were wearing “full gear”, adding: “The first bang was nothing like I’d heard before.”
Police are also at an address on Caledon Road in Newham, east London.
A police van is parked in the middle of the road and the street of terraced houses is cordoned off at both ends.
A woman called Sonia said police raided the house next to the one she lives in at 4am. She said she was woken up by the noise and could hear shouts of “On the floor, on the floor, on the floor” coming from next door.
“And after, people screaming scared, and boom boom boom,” she said, adding that she could hear an explosion and four or five gunshots. The noise was so loud and she and her housemates thought it was taking place in their house.
“We were very scared,” she said, adding that glass was smashed at the front of her house.
She said she believes the people who live in the house are Muslim, adding that it is a family which includes two sons.