It is almost impossible to put into words how horrible the attack on the Manchester Arena on Monday night was. The news will terrify any parent. For anyone who’s ever been near to a terrorist attack, it will provide a reminder of the pain that such events inflicts. This morning, Tessa Jowell reminded us on the Today programme of the long-lasting effects of these atrocities on relatives and friends of the casualties. She said that support for families affected should last “10 years” at least, drawing on her experiences of coordinating the response to the 7/7 attacks. That did not surprise me at all.

Manchester is suffering now – but its spirit will overcome this atrocity | Owen Jones Read more

On 27 March 1976, when I was 10 years old, my mother took me, my sister and two of our friends to the Ideal Home Exhibition at London’s Olympia. It was exciting to be among the 20,000 or so visitors and to see the lavish decorations and demonstrations of innovative gadgets. At some point in the afternoon, my friend Tanya and I waited by a waste bin while my mother and the others went to the toilets.

When they returned, we alighted a nearby escalator to the floor above. As we stepped off at the top there was a monumental, ear-splitting boom. People were flung in all directions, there was smoke, screaming, crying, broken glass all over the floor and what seemed like torrents of blood. The bin that we had been standing beside only seconds earlier, it transpired, had contained a bomb planted by the Provisional IRA.

An amplified voice instructed everyone to evacuate the building immediately and mass panic ensued. My mother told us to stand still – she was concerned we would be trampled – so we did, unable to avoid witnessing the grisly scene below. A man lay on the floor and we watched as what was left of one of his legs was propped up on a barrel to slow the escaping blood while people ripped fabric from stalls to mop up the other 84 casualties, many of whom had shards of glass protruding from their flesh.

Play Video 0:47 'All I could hear was screaming': Manchester bombing witnesses – video

As terrorist attacks go, this one was relatively minor: there was no structural damage to the building or immediate deaths, but without doubt there was damage to some of those who witnessed it. In the months ahead I had trouble blocking out the images of what I had seen and struggled to come to terms with the realisation that grownups could panic like children. When my mother planned trips to London, I was often unable to go, being struck down with mysterious nausea and vomiting. Curiously, no one ever put two and two together and it was years before I realised the cause of this “illness”.

My friend Tanya suffered more: sudden movement or sounds would incite severe anxiety; she later developed claustrophobia, agoraphobia and panic attacks. She became obsessed with unattended packages, the potential threat of which was on everyone’s mental radar at the time due to the continued IRA bombing campaign. To this day she will only sit in an aisle seat at the cinema or in a theatre. Tanya was clearly suffering from post-traumatic stress disorder.

Terrorism, be it executed by a solo operator or an organised political outfit, can never be wiped out. The response should be to mourn, to make sure everyone has the help they need, but not to let society change in the way terrorists wish it to. As the Manchester mayor Andy Burnham stated: “We are grieving today, but we are strong. Today it will be business as usual as far as possible in our great city.”

Thankfully counselling for those immediately affected – as well as the less obvious victims, the onlookers – is now more readily available. Like others today, I am hoping that all those still missing are found safe and well. And that, for those who witnessed the tragic event, or have lost loved ones, we can give them whatever support they need to come to terms with what has happened.