Amber Rudd has announced a review of how the authorities dealt with recent terror attacks in the UK.
The Home Secretary said former independent reviewer of terrorism legislation David Anderson will lead the review, which will see if “lessons can be learned”.
Her announcement follows terror attacks in Westminster, Manchester, London Bridge and Finsbury Park.
Speaking in the Commons, Ms Rudd reiterated more must be done to tackle the extremists who seek to “radicalise and weaponise” young people in Britain.
She said: “Doing more also means asking difficult questions about what has gone wrong.
“In light of the terror attacks in London and Manchester, Britain’s counter-terror strategy will be reviewed to make sure the police and the security services have what they need to keep us safe.
“In addition to this, there will be a review of the handling of recent terror attacks to look at whether lessons can be learned about our approach.
“I’m pleased to announce that David Anderson, former independent reviewer of terrorism legislation, will be overseeing it.”
Ms Rudd earlier said the four attacks had seen “136 innocent people dead and over 150 hospitalised”, adding: “A tragic loss of innocent life.”
She told the Commons a “new phase of global terrorism” is beginning, noting: “We now believe we’re experiencing a new trend in the threat we face.”
MPs heard that 13 plots linked to or inspired by Islamist extremists were foiled between June 2013 and the Westminster Bridge attack in March this year.
Ms Rudd added that five plots have been prevented since March, with three Islamist plots succeeding - while the Finsbury Park attack has also taken place in which a van driver targeted an area busy with worshippers attending Ramadan night prayers at the nearby mosque.
She said: “We must do more to defeat ideologies of hatred by turning people’s minds away from violence and towards pluralistic British values.
“We must make sure that these ideologies are not able to flourish in the first place. We must do more to force tech companies to take down terror-related content from their platforms.
“And we must also do more to identify, challenge and stamp out extremism that lurks in our communities.”
Ms Rudd said that is why the Government wants to set up a Commission for Countering Extremism.
Shadow home secretary Diane Abbott said ministers should focus on boosting police resources over creating more laws, adding: “Cuts have consequences.”
She told MPs: “We will look at all legislative proposals that the Government brings forward on their merits but we believe that resources are at the heart of this, not just new legislation.
“In this we are supported by Max Hill, the independent reviewer of terrorism legislation. His objective view is that current powers are sufficient.”
Ms Abbott pressed the Home Secretary to commit to halting cuts to policing budgets and asked whether “austerity still applies to our safety”.
Quoting a letter outlining concerns from the UK’s top counter-terrorism officer over resources, she said: “What (Metropolitan Police Assistant Commissioner) Mark Rowley is saying is that cuts have consequences and your cuts run the risk of putting us all in danger.
“Our understanding on this side is you are going to cut again.”
No community should be singled out as the only source of terror, Ms Abbott said, as she praised the actions of imam Mohammed Mahmoud, who shielded the Finsbury Park terror suspect from angry crowds until police arrived, saying he “exemplifies the best of the values of Islam ... the best of British values”.
She added: “I believe the way that multi-faith and inter-community co-operation is working in practice in that area of London shows us the way forward in the end, in the long run, in contesting the ideology of fear and violence and terror.”