When the first ominous reports began to circulate of an explosion towards the end of a sold-out concert in the 21,000-capacity Manchester Arena, there were immediate fears that serious casualty levels were likely to follow.
By early yesterday, revulsion grew as it emerged that 22 people had died, with up to 60 injured, in an attack by a suicide bomber who had managed to gain entry to the foyer as the crowds started to leave.
However, probably the darkest sense of despair accompanied the realisation that the perpetrator had deliberately targeted fans of the US singer Ariana Grande in the knowledge that they were overwhelmingly girls in their teens or even younger.
Previous outrages by Islamic State extremists in western Europe had usually been either entirely random in nature or at least in general terms aimed at mainly adult groups and gatherings.
While those were vile acts, there was something particularly chilling about the decision by an individual, possibly with the support of others, to strap a bomb to his chest and deliberately detonate it after walking into an auditorium packed with excited children and their families.
It was probably clear before the Manchester catastrophe that existing security precautions in urban centres would have to be comprehensively reviewed but there can now be no doubt that urgent changes are needed.
Full public cooperation will be required as the authorities set out to protect ordinary citizens, with specific attention paid to events of all descriptions which are expected to attract significant attendances.
What is equally essential is that the key measures are directed against the handful of fanatics who intend to inflict carnage on western society and not towards the vast majority of Muslims who are appalled by terrorism in all its forms and simply want to live in harmony with their neighbours of all religions and none.
Members of the Irish community in England will not need to be reminded about the cloud of suspicion which descended on them after the last bombing in Manchester which murdered innocent children.
On that shameful occasion in 1993, devices planted by the IRA killed 12-year-old Tim Parry and three-year-old Johnathan Ball outside a busy shopping complex.
The most compelling voice in the aftermath of the tragedy belonged to Tim’s father, Colin Parry, who became a tireless campaigner for peace and reconciliation.
During media interviews yesterday, Mr Parry referred poignantly to the inspiration he received from the late Gordon Wilson, who lost his daughter, Marie, in the IRA’s Remembrance Day atrocity at Enniskillen in 1987.
Mr Wilson’s message, that love will always triumph over hate, resonates as powerfully today as it did 30 years ago, and offers us hope at a time when it is most badly needed.
