Theresa May condemned the terror attack near Finsbury Park Mosque as "insidious and destructive" as she vowed to "stop at nothing" in the battle against extremism.
Speaking outside Downing Street, Mrs May called the terror attack a targeting of the "ordinary and the innocent" and said "hatred and evil" would never succeed.
It came after one person was killed and ten others injured after a van driver allegedly screaming "I want to kill all Muslims" ploughed into worshippers near Finsbury Park mosque on Monday.
The Prime Minister pledged to review security at mosques across Britain in wake of the attack, with police presence already heightened at some London mosques.
Mrs May was speaking following a meeting with security officials and ministers in the Government's Cobra emergency committee in Whitehall.
She said: "This morning we have seen a sickening attempt to destroy those freedoms and to break those bonds of citizenship that define our United Kingdom.
"There has been far too much tolerance of extremism in our country over many years and that means extremism of any kind, including Islamophobia."
The Prime Minister confirmed that that police investigating the attack believe the man who drove a van into worshippers outside acted alone.
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Police statement on terror attack in Finsbury Park
She renewed her pledge to review the Government's counter terror strategy and create a new commission for countering extremism.
The attack is the second terrorist incident to hit the capital's streets in just over two weeks, with eight people killed in the London Bridge atrocity on June 3.
Mrs May added: "This extremism is every bit as insidious and destructive to our values and our way of life. And we will stop at nothing to defeat it.
"Today's attack falls at a difficult time in the life of this city, following on from the attack on London Bridge two weeks ago and of course to unimaginable tragedy of Grenfell Tower last week.
"This is an extraordinary city of extraordinary people. It is home to a multitude of communities that together make London one of the greatest cities on earth - diverse, welcoming, vibrant compassionate, confident and determined never to give in to hate.
"These are the values that define this city. These are the values that define this country. These are the values that this Government will uphold. These are the values that will prevail."
A man was tackled to the floor and detained by onlookers after the van veered into a crowd of worshippers who had just finished prayers at the mosque in Seven Sisters Road just after 12am on Monday.
A 48-year-old man has been arrested on suspicion of attempted murder.
Mrs May praised the bravery of the people who detained a man at the scene and said the "heroism" of people in the aftermath of attacks was a "tribute to the spirit of the city". © Provided by Independent Print Limited © Provided by Independent Print Limited