Student georgina callander, who was 19. Many others are still missing this is my daughter, olivia, i havent seen her since 5. 00pm last night. She was at the Ariana Grande concert with her friend. Im worried sick. If anyone has seen her, please contact the police. We will bring you the latest from here in manchester on the Bbc News At One. This has been the most horrific incident we have ever faced here in Greater Manchester and one that we all hoped we would never see. Stay with bbc news for all the developments from manchester, where Police Patrols have been stepped up including the deployment of armed officers. Good afternoon and welcome to the Bbc News At One from manchester, which has experienced the uks worst Terrorist Attack since the July 7th Attacks in london in 2005. 22 people have been killed, and 59 injured they are now being treated at a number of hospitals in and around manchester. They were among thousands of people who had come to the concert of Ariana Grande and at the concert of Ariana Grande and at the end of the concert at around 10. 30 last night, the explosion went off. Lets talk you through what we know so far. Greater Manchester Police were called to the arena at 10. 33pm. The Prime Minister called the attack on fans at an Ariana Grande concert here an act of appalling, sickening cowardice. The explosion happened in the arenas foyer last night, as people began streaming through the doors at the end of the concert. Police said the lone male attacker, who died in the blast, detonated an Improvised Explosive Device. Security has been tightened in the Wa Ke Security has been tightened in the wake of the attack. Surrounding streets were sealed off and nearby Victoria Station closed. A warning that this report, from richard galpin, contains scenes you might find distressing. 0h oh my god. What is going on . Something has happened. What had been a night of online elation for thousands of teenagers. 0h, been a night of online elation for thousands of teenagers. Oh, my god. Turned to absolute panic. Everyones heard what they think is a bomb going off. And the only thing now is to get out of this arena, as fast as possible. It was shocking. Like, just heard this massive bang. Then eve ryo ne just heard this massive bang. Then everyone started running towards us, screaming and crying. Everyonejust jumping over us to get out. Screaming and crying. Everyonejust jumping over us to get Outlj Screaming and crying. Everyonejust jumping over us to get out. I saw parents with kids running out with blood all over them. I picked this lady up who said she was looking for hergrand kids, lady up who said she was looking for her grand kids, who couldnt find her grand kids, who couldnt find hergrand kids, her grand kids, who couldnt find her grand kids, she picked up a young girl on the floor who was Cove Red Young Girl on the floor who was covered in blood with parents laying next to them. It is just all bizarre. The glass and nuts, metal nuts that have been in the device that have exploded. I cant think of Anything Else thats got nuts that would be flying around. Which way . Which way. Come on. Traumatised and uncertain what to do, many of the youngsters just keep running. Uncertain what to do, many of the youngstersjust keep running. Some, searching for their parents, whod been waiting to pick them up at the end of the concert. Others looking for relatives and friends whove gone missing and today some families are still trying to find their children. The family of Olivia Campbell hardy have heard nothing from her since she went to last nights concert she was at the concert. Shes just seen the support act and said she was having an amazing time and thanking me for letting her go. She was with her friend adam. Adam was found, he is in hospital. But olivia has not been found yet. Im at home phoning everybody, hospitals, police, all these centres that are the children have been put in. Her dad is actually in manchester looking for her. Ive got friends out looking for her. Ive got people i dont even know out looking for her. Social media has been wonderful. I dont know what i wouldve done without them. Its made it so aware that shes misand theres missing and theres thousands of people who know shes missing, have seen her picture and there are people out looking for her that i dont know. I cant thank these people enough for giving their time up. Children are amongst the many casualties. All the major hospitals in Manchester Being used last night to receive the injured and the dead. And this morning, the Police Confirmed it was a Terrorist Attack, carried out by a suicide bomber. This has been the most horrific incident we have ever faced here this has been the most horrific incident we have everfaced here in Greater Manchester and one that we all hoped we would never see. Families and many young people were out to enjoy a concert at the Manchester Arena and have sadly lost their lives. We believe at this stage that the attack last night was conducted by one man. The priority is to establish whether he was acting alone or as part of a network. The attacker, i can confirm, died at the arena. We believe the attacker was carrying an Improvised Explosive Device which he detonated, causing this atrocity. Improvised explosive device which he detonated, causing this atrocitym Downing Street, flags are flying at half mast in the aftermath of the worst Terrorist Attack in britain since the Suicide Bombings on London Transport 12 years ago. All acts of terrorism are cowardly attacks on innocent people. But this attacks on innocent people. But this attack stands out for its appalling, sickening cowardice. Deliberately targeting innocent defensive children and young people, who should have been enjoying one of the most memorable nights of their lives. Let us remember those who died and let us celebrate those who helped, safe in the knowledge that the terrorists will never win and oui the terrorists will never win and our values, our country and our way of life will always prevail. The horror of what happened at the arena Last Night Led to many ordinary people offering to help. Taxi drivers providing free lifts for those who couldnt get back home. Others Offering Rooms for anyone needing somewhere to sleep. As for who was responsible for this attack . The Police Believe they do know the persons identity. And already, a 23 year old man has been arrested in connection with the bombing. Also this morning, the first victim has been named. Shes18yearold georgina calendar, on the left in this photograph. Posing with the singer, Ariana Grande, who was performing at last nights concert. The children at the concert would never have imagined he theyd end up like this, having to escape a Terrorist Attack. But its clear they were deliberately targeted and that has provoked both such and revulsion in this country and Around The World. Terrifying accounts are emerging from Concert Goers, as they tried you can just see the stairs there, that many people ran down, after the explosion went off at about 0. 30 last night. People have been talking 10. 30 last night. People have been talking 10. 30 last night. People have been talking about how they got separated from their loved once and the desperate search for loved once who are missing. Also talking about how they saw the explosion and saw nuts and bolts flying through the air. Danny savage reports and you may find some pictures in the report distressing. This is my daughter owe livia. I have not seen her since 5. 00 last night. She was at the Ariana Grande concert with her friend. Night. She was at the Ariana Grande concert with herfriend. Im worried sick. If anybody can seen her, contact the police, even if you think you have seen her, just let the police know, please. An appeal from a desperate mum. Charlotte campbell hasnt heard from her daughter, olivia, who was at the concert last night. Her family has been out searching for the teenager for hours i need my daughter home. I need to know where she is. On the wards of numerous hospitals across manchester, the casualties have been treated and the bore received are bereaved are being comforted we werent sure what happened. We thought it was a balloon that had popped. Or possibly a wire or something. We didnt think it was an explosion. The minute we heard the bells we ran up to our hotel. Outside city centre hotels, survivors recounted the horror of what happened inside the arena. Towards The Last Song she let a load of helium balloons down, quite a lot. A bang happened. We thought i mean we looked at each other and we we re mean we looked at each other and we were like, no, no, it cant be something that you see on the news, that doesnt happen it people like us. That doesnt happen it people like us. Its the balloons. Everyone calmed around us and all of a sudden, everyone started screaming and running in every direction. There was one girl there, she tumbled over the seats. She went over about three seats. It was awful. She fell. On social media, numerous appeals soon appeared for Concert Goers to contact home. Deborah hutchinson from newcastle wrote my daughter, Courtney Boyle and partner philip have gone missing in an attack in manchester. Please share and help find them, i need them home safe. People who were there, tried to offer help online, too. Sharing pictures of missing people. People who need help, who have nowhere to sleep, need food and water. Trying to get awareness out for people willing to help. Picture of chaos and panic emergedlj heard picture of chaos and panic emerged heard an explosion, i was like we need to run, we started running all the way down to the doors to the hoe tempt all i heard was people screaming and crying and running everywhere. It is harder to imagine a softer target for this attack. So many of the teenagers and children who were there last night were given tickets as a christmas or birthday present. Thousands of children and young people have gone to school this morning, knowing of a friend or a friend of a friend who was at the concert last night and now numerous families are having to arrange the funeral of a son or daughter, who went out yesterday evening, so excited, ahead of that concert. Danny savage, bbc news. We now know, 22 people killed, 59 injured. The injured are being treated at a number of hospitals in and around manchester. The Prime Minister has been praising the work of paramedics, doctors and nurses as they try to care for those people, many of them with life threatening injuries. Lets get the latest now from Stepping Hill Hospital in Greater Manchester. What is the picture there . Good afternoon, ben, we know a fleet of 60 ambulances, drawn notjust from Greater Manchester, from the North West Ambulance service but neighbouring services in the midlands and north wales, ferried the 59 most seriously injured people to eight homingts in the Greater Manchester area, including major Trauma Centres at wythenshawe and manchester Royal Infirmary but so many people were badly injured other hospitals took them. Here at stepping hill nine people were admitted with major trauma injuries. We know at least one was a child. Three of those people were still being operated own this morning, so they are in, still, a very serious condition. But here at the hospital, weve heard stories of staff coming in overnight to help out e and to help out in Operating Theatres and we know that the hospital actually had to turn some staff away because the next couple of days are also going to be challenging for the nhs across the region but we do know that they say they have enough blood from Blood Donation centres to treat all those who need it. So they are asking people to think carefully before they go to a e. While services are operating as normal, they will be under bigger pressure. Thank you very much, dominic. The Prime Minister has chaired a meeting with cobra in Downing Street. We gather there will be another meeting later today. She is travelling to manchester with the Election Campaign suspended. She is travelling to meet Greater Manchester police and other Senior Police commanders. She has described this as a callous, Terrorist Attack. Paul adams has this report. Forensic police at the scene this morning, beginning to answer key questions. How was this attack carried out . What, if any wider lessons need to be learned . In and around the venue, there will be clues. In london, ministers gathered for a meeting of the governments top security committee, cobra. After the first Mass Casualty Attack in britain for a dozen years. In britain for a dozen years, what level of danger does the country now face . The threat level remains at severe. That means a Terrorist Attack remains highly likely. But the independent joint Terrorism Analysis Centre which sets the threat level on the basis of the intelligence available to them, will continue to assess this throughout the day and in the days ahead. Not since 2005 and the attacks of 7 7 have the authorities had to deal with something on this scale. Plenty of plots have been foiled in the years since and Counterterror Police are still making arrests at an average rate of one day. But the Public Perception of the threats we face has changed. Four years ago, Fusilier Lee Rigby was hacked to death near a london barracks and two months ago, an attacker using a car and a knife killed five people in westminster. Last nights atrocity was more sophisticated. This attack does involve someone being able to get hold of explosives, or make explosives. Turn them into a belt and then make the effort of putting bolts and things in that in order to kill people and then has used it at one of the most effective times. So, this is a much more professional style of attack. Does this mean big venues up and down the country need better protection . Theres no evidence yet that last nights attacker passed unchallenged through security, but some concertgoers have voiced concerns. A few people we spoke to, like friends that we met before and after the gig, they said their bags were not checked. Usually, i am quite a regular gig goer and i am used to getting my bags checked for security purposes. But there was none. We just went straight in. A brief moment of panic this morning outside Manchesters Arndale centre. Shoppers said they heard a bang. The danger, if any, passed, but the arndale has been targeted twice in the past. In 1996, it was wrecked by an ira bomb. And eight years ago, a plot involving a car bomb and suicide vests was foiled. A pakistani student was convicted in the us in 2015. Investigators at the arena will want to know how and where the attacker obtained the ingredients for his bomb and crucially, was he acting alone or part of a cell . In london, the metropolitan police commissioner, Cressida Dick said more officers have already been put on duty, the impact of last nights attack will be felt right across the country. Paul adams, bbc news. We can talk to vicki young in Downing Street and Daniel Sandford he is at Greater Manchester police headquarters. Daniel, so called Islamic State claiming responsibility, what more do we know about the attack and whether it was the work of one man or perhaps unorganised group, and organise sell . First of all we have to set aside the claim of responsibility by Islamic State. They have had a tendency to do that regardless of whether or not they have been involved in recent years. At this point there appears to have been one attacker who was carrying and explosive device and he was killed. Police now need to find out where it was made because once they have found back, they can work out whether he made the device by himself or whether he was assisted by others in making the device. But then opens up a wider network. We know there are expected to be a number of arrests. At 2