The head of the MI5 has warned that the UK is facing its biggest challenge yet as terrorism continues to evolve.
Speaking yesterday in central London, Andrew Parker said the country was dealing with "more threat, coming at us more quickly," adding that it was "sometimes harder to detect".
The country's threat level remains at severe.
Threats were being identified "day in and day out" and the challenge that we face "is undoubtedly a stark one", the intelligence boss said. MI5 is running 500 live operations involving 3,000 individuals involved in extremist activity in some way.
Some 20 attacks have been foiled in the last four years, including seven in the last seven months, he said, adding they were all related to what he described as Islamist extremism.
But the UK has been rocked by five attacks this year, including a suicide bomb attack at the end of an Ariana Grande concert at Manchester Arena in May, which killed 22 people.
April's attack near the Houses of Parliament claimed the lives of five people, while eight were killed during a knife attack in Borough Market, near to London Bridge.
June saw a man drive a van into a crowd of worshippers near a mosque in London, while a homemade bomb partially exploded in tube train at Parsons Green station last month, injuring 30 people.
But Parker insisted it was a challenge the intelligence agency and its partners were "rising to and are facing down".
He said: "We face this new order of challenge from a position of strength. The UK has world-class intelligence agencies and counter terrorism policing. We are developing, growing and sharpening our capabilities all the time."
"We are committed to this for the long haul," he added. "Our unrelenting focus will remain on doing everything in our power every day to keep Britain safe."