The Prime Minister has condemned last night's terrorist attack in Manchester as an act of "appalling, sickening cowardice" as she confirmed that police believe they have identified the perpetrator.
In a strongly-worded statement outside Downing Street, Theresa May described the incident as one of the worst terrorist attacks to take place in the UK that "coldly" targeted "the youngest people in our society".
The speech, which followed this morning's meeting of the COBR committee, was the second time Mrs May has had to address the nation following a terrorist attack since entering Number 10.
It saw her pay tribute to the "bravery" of the emergency services and praise the "countless acts of kindness that brought people closer together" as she stressed that British values "will always prevail".
"It is now beyond doubt that the people of Manchester and of this country have fallen victim to a callous terrorist attack, an attack that targeted some of the youngest people in our society with cold calculation," Mrs May said.
"This was among the worst terrorist incidents we have ever experienced in the United Kingdom. And although it is not the first time Manchester has suffered in this way, it is the worst attack the city has experienced and the worst-ever to hit the north of England.
"The explosion coincided with the conclusion of a pop concert, which was attended by many young families and groups of children.
"All acts of terrorism are cowardly attacks on innocent people, but this attack stands out for its appalling, sickening cowardice, deliberately targeting innocent defenceless children and young people who should have been enjoying one of the most memorable nights of their lives.
"We struggle to comprehend the warped and twisted mind that sees a room packed with young children not as a scene to cherish but as an opportunity for carnage.
"But we can continue to resolve to thwart such attacks in future - to take on and defeat the ideology that often fuels this violence, and if there turn out to be others responsible for this attack to seek them out and bring them to justice."
Mrs May stated that police and security services "are working at speed" to establish the full detail surrounding the attack, which has left 22 dead.
She also revealed that security services believe they know the identity of the perpetrator but cannot yet confirm his name.
She added that the threat level will remain at severe - which means a terrorist attack remains highly likely.
However, the Joint Terrorism Analysis Centre, which sets the threat level, will continue to assess this throughout the day.
"At terrible moments like these, it is customary for leaders, politicians, and others to condemn the perpetators and declare that the terrorists will not win," she said.
"But the fact we have been here before and the fact we need to say this again does not make it any less true.
"For as so often while we experienced the worst of humanity in Manchester last night, we also saw the best. The cowardice of the attacker met the bravery of the emergency services and the people of Manchester.
"There will be difficult days ahead. We offer our thoughts and prayers to the family and friends of those affected... and we all, every single one of us stand with the people of Manchester at this terrible time.
"And today, let us remember those who died, and let us celebrate those who helped, safe in the knowledge that the terrorists will never win and our values, our country and our way of life will always prevail."
All major parties have agreed to suspend campaigning today. It is understood that the Prime Minister will travel to Manchester to meet police and local leaders ahead of another meeting of COBR this afternoon.