It was a concert by the American singer Ariana Grande.

Her Twitter bio declares she is a “dangerous woman”. But in truth, a lot of her fans are teenage girls, teenage girls who get taken to her concerts by their mums or dads.

On Monday night, it was these fans who had packed into a sold-out concert at the Manchester Arena, the first date of Grande’s UK tour, when what police are treating as a terror attack, left Britain reeling just two weeks away from a general election.

Armed police officers stand near the Manchester Arena ( Reuters )

It was these people who suffered from what were described as shrapnel injuries, when they should have been been celebrating a performance by the young American star, making their way home laughing and smiling, buoyed by her music, and the thrill of seeing her perform live.

Details of the horror that befell Manchester are still emerging. Reports from the US, suggest British police believe the 19 deaths and more than 50 injuries, were the work of a suicide bomber. If indeed, the incident is confirmed as a terror attack, it will be the deadliest of its type since the July 7 bombing attack in 2005 that killed 52 people.

It has long been said that the intention of a terror attack is to spread terror. Manchester, and Mancunians, responded remarkably in the aftermath of what happened outside, or in the foyer, of the concert hall.

Taxis drivers gave free rides home, hotels opened up their rooms in hospitality. Ordinary people offered cups of tea.

But it would be an extraordinary person who was not simply stunned, but utterly staggered and terrified, by what transpired in Manchester.

Dashcam video appears to show moment of Manchester explosion

Ian Hopkins, the grim-faced Chief Constable of the city's police force summed up the mood in a statement, delivered in the early hours from the steps of police headquarters.

“We are currently treating this as a terrorist incident until we have further information,” he said. “This is clearly a very concerning time for everyone. We are doing all that we can.”

Hopkins can be forgiven if “very concerning” was an understatement of no small degree.

Manchester explosion in pictures Show all 37 1 / 37 Manchester explosion in pictures Manchester explosion in pictures People running down stairs as they attempt to exit the Manchester Arena after a blast, where U.S. singer Ariana Grande had been performing, in Manchester Twitter/@ZACH_BRUCE/ via REUTERS Manchester explosion in pictures Helpers attend to people inside the Manchester Arena after a suspected suicide bomber detonated an explosive device at the end of an Ariana Grande concert, killing 22 people PA wire Manchester explosion in pictures Armed officers guard outside a hotel near the Manchester Arena following reports of an explosion, in Manchester, Britain EPA Manchester explosion in pictures Police officers are seen outside the Manchester Arena, where U.S. singer Ariana Grande had been performing, in Manchester, northern England Reuters Manchester explosion in pictures MANCHESTER, ENGLAND - MAY 23: Police escort members of the public from the Manchester Arena on May 23, 2017 in Manchester, England. An explosion occurred at Manchester Arena as concert goers were leaving the venue after Ariana Grande had performed. Greater Manchester Police have confirmed 19 fatalities and at least 50 injured. (Photo by Christopher Furlong/Getty Images) Getty Images Manchester explosion in pictures MANCHESTER, ENGLAND - Emergency services arrive close to the Manchester Arena on May 23, 2017 in Manchester, England. There have been reports of explosions at Manchester Arena where Ariana Grande had performed this evening. Greater Manchester Police have have confirmed there are fatalities and warned people to stay away from the area. (Photo by Dave Thompson/Getty Images) Getty Images Manchester explosion in pictures MANCHESTER, ENGLAND - MAY 23: Police escort members of the public from the Manchester Arena on May 23, 2017 in Manchester, England. An explosion occurred at Manchester Arena as concert goers were leaving the venue after Ariana Grande had performed. Greater Manchester Police have confirmed 19 fatalities and at least 50 injured. (Photo by Christopher Furlong/Getty Images) Getty Images Manchester explosion in pictures Medics deploy at the scene of a reported explosion during a concert in Manchester, England on May 23, 2017. British police said early May 23 there were "a number of confirmed fatalities" after reports of at least one explosion during a pop concert by US singer Ariana Grande. Ambulances were seen rushing to the Manchester Arena venue and police added in a statement that people should avoid the area / AFP PHOTO / Paul ELLIS (Photo credit should read PAUL ELLIS/AFP/Getty Images) AFP/Getty Images Manchester explosion in pictures Police and fans close to the Manchester Arena, after reports of an explosion Getty Images Manchester explosion in pictures There have been reports of explosions at Manchester Arena where Ariana Grande had performed Getty Images Manchester explosion in pictures Police deploy at scene of explosion in Manchester, England, at a concert in Manchester Arena AFP/Getty Images Manchester explosion in pictures Police stand by a cordoned off street close to the Manchester Arena Getty Images Manchester explosion in pictures Police deploy at scene of explosion in Manchester, England AFP/Getty Images Manchester explosion in pictures Police deploy at scene of a reported explosion during a concert in Manchester, England, on May 23, 2017. British police said early May 23 there were "a number of confirmed fatalities" after reports of at least one explosion during a pop concert by US singer Ariana Grande. Ambulances were seen rushing to the Manchester Arena venue and police added in a statement that people should avoid the area AFP/Getty Images Manchester explosion in pictures An ambulance drives away from the Manchester Arena, where U.S. singer Ariana Grande had been performing, in Manchester Reuters Manchester explosion in pictures Police escort members of the public from the Manchester Arena in Manchester, England. Getty Images Manchester explosion in pictures A woman sits in the street in a blanket near the Manchester Arena as police guard the area following reports of an explosion, in Manchester, Britain EPA Manchester explosion in pictures Two women wrapped in thermal blankets stand near the Manchester Arena, where US singer Ariana Grande had been performing, in Manchester Reuters Manchester explosion in pictures A Royal Logistic Corps (RLC) bomb disposal robot is unloaded outside the Manchester Arena following reports of an explosion, in Manchester. At least 19 people have been confirmed dead and others 50 were injured, authorities said. It is being treated as a terrorist incident until police know otherwise EPA Manchester explosion in pictures A Royal Logistic Corps (RLC) bomb disposal robot is unloaded outside the Manchester Arena following reports of an explosion, in Manchester EPA Manchester explosion in pictures Members of the public receive treatment from emergency service staff at Victoria Railway Station close to the Manchester Arena on May 23, 2017 in Manchester, England. There have been reports of explosions at Manchester Arena where Ariana Grande had performed this evening. Greater Manchester Police have have confirmed there are fatalities and warned people to stay away from the area Getty Images Manchester explosion in pictures Armed police after a suspected terrorist attack at the Manchester Arena at the end of a concert by US star Ariana Grande left 19 dead PA wire Manchester explosion in pictures Emergency services arrive close to the Manchester Arena in Manchester Getty Images Manchester explosion in pictures An amoured police vehicle patrols near Manchester Arena in Manchester Getty Images Manchester explosion in pictures A man carries a young girl on his shoulders near Victoria station in Manchester AFP/Getty Images Manchester explosion in pictures Police officers stand at the Miller Street and Corporation Street Crossroads, in front of the Manchester Arena in Manchester, England Getty Images Manchester explosion in pictures Police block a road near to the Manchester Arena in central Manchester, England AP Manchester explosion in pictures Armed police patrol near Victoria station in Manchester, northwest England. Twenty two people have been killed and dozens injured after a suspected suicide bomber targeted fans leaving a concert of US singer Ariana Grande in Manchester Getty Images Manchester explosion in pictures Police forensic officers leave the Manchester Arena as they investigate the scene of an explosion in Manchester Getty Images Manchester explosion in pictures A forensic officer collects evidence on a walkway between Victoria station and Manchester Arena following a deadly terror attack in Manchester, Getty Images Manchester explosion in pictures A woman and a young girl wearing a t-shirt of US singer Ariana Grande talks to police near Manchester Arena following a deadly terror attack in Manchester, Getty Manchester explosion in pictures epaselect epa05982725 Susan Walton and daughter Katie, 10 (pictured), who attended the concert of Ariana Grande at the Manchester Arena, are seen in Manchester, Britain, 23 May 2017. According to a statement released by the Greater Manchester Police on 23 May 2017, police responded to reports of an explosion at Manchester Arena on 22 May 2017 evening. At least 19 people have been confirmed dead and around 50 others were injured, authorities said. The happening is currently treated as a terrorist incident until police know otherwise. According to reports quoting witnesses, a mass evacuation was prompted after explosions were heard at the end of US singer Ariana Grande's concert in the arena. EPA/NIGEL RODDIS EPA Manchester explosion in pictures Mayor of Greater Manchester Andy Burnham and Manchester City Council Leader Sir Richard Leese speak to the media outside Manchester Town Hall after a suicide bomber killed 22 people, including children, as an explosion tore through fans leaving a pop concert in Manchester Dave Higgens/PA Wire Manchester explosion in pictures The media gather behind a police cordon in Manchester Getty Images Manchester explosion in pictures Flowers left close to the Manchester Arena, the morning after a suicide bomber killed 22 people, including children, as an explosion tore through fans leaving a pop concert in Manchester Danny Lawson/PA Wire Manchester explosion in pictures Ariana Grande concert attendees Karen Moore and her daughter Molly Steed, aged 14, from Derby, leave the Park Inn where they were given refuge after last night's explosion at Manchester Arena Getty Manchester explosion in pictures Signs saying 'We love Manchester' are displayed in a window in Manchester, England Getty Images

Prime Minister Theresa May is to confer with Britain’s top security committee - a so-called Cobra meeting - on Tuesday morning. Her hope, and all of those who meet with her in the shadows of Whitehall, will be that this was a one-off incident, not the start of something even more horrible.

As Jeremey Corbyn offered his condolences, May said she was suspending her election campaign to deal with what had transpired. That is only right and correct.

But if the intention of those who commit acts of terror is to disrupt ordinary life, then the only possible response is not to let that happen. That is not to say police should not track down who was responsible for such vile murder. That is not to say the security services should not step up their efforts and do all they can to stop a repeat of such slaughter.

Manchester explosion: Witnesses describe horror as 19 dead in arena blast

Nor is it about what lots of Britons like to call the Dunkirk spirit, or about showing a stiff upper lip.

Rather, it is a merely an assessment of the options that are available to us, the ordinary people, those without superhuman powers.

We’re not actually equipped to do that much at all, other than to try to carry on, to not allow ourselves to be terrorised, to not stop living our lives. And that means means continuing with the general election May felt obliged to call, or keep on buying tickets to see the likes of Ariana Grande.