And so we continue to do precisely the opposite of what we should do
Anyone who remembers the IRA's bombing campaigns in the UK will know that the governmental response at the time, whilst often hugely overblown in its treatment of Irish people, was essentially to ensure "business as usual" for as many people as possible.
Since 9/11 the US, and by extension the UK because we now apparently take the lead from them in this area, have operated quite the opposite policy, and it is a disaster. They and we now jump at the slightest squeak, talk up every threat, and promote the idea that if one terrorist attack is prevented then this policy is justified.
No, it isn't.
We need to say to anyone who wants to change us via terrorism that while we will do our best to stop them, we will not change our lives to achieve that. We need to say that you can continue to blow us up, but you will not change our minds. We need to tell them that they will not make us run scared by threat alone. To make a difference they will have to penetrate our defences every time. A threat, or a failed attempt, should have no impact on our lives.
It seems cliched and obvious to say it, but terrorists win when we react to them, in any way. Yes we should continue to act to prevent acts of terror when we discover them; but we must get far better and facing down the threat, telling and showing them that we are not scared of them, and that we will not capitulate.
Otherwise we have already lost.