Theresa May says that the unprecedented new wave of eight attacks in the last three months means "enough is enough".
A major overhaul of security powers is now necessary, Mrs. May also said, as she ordered a full scale review of the country's counter-terrorism strategy.
Dressed in black, the PM said: "Terrorism breeds terrorism, and perpetrators are inspired to attack not only on the basis of carefully-constructed plots after years of planning and training but by copying one another and often using the crudest of means of attack. We cannot and must not pretend that things can continue as they are. Things need to change."
Mrs. May pledged:
- A fresh offensive to defeat the evil ideology of Islamist extremism that is brainwashing young minds by pushing Britain's values far harder.
- A clampdown on safe spaces in Britain where extremism breeds: be it in prisons, faith schools, mosques or universities.
- Appointment of a new Extremism Commissioner.
- A full overhaul of security powers, including longer jail terms for terror offenders who commit lower level offences such as incitement.
- To redouble her efforts to forge an international agreement to stop internet companies from allowing terror to breed online
Branding the war against Islamist extremism as "one of the great challenges of our time", Mrs May insisted she no longer give any quarter to anyone who conducts or condones it.
She said: "While we have made significant progress, there is to be frank, far too much tolerance of extremism in our country. So we need to become far more robust in identifying it and stamping it out across the public sector and across society.
The PM added: "United, we will take on and defeat our enemies".