The first emotion felt by those reading about the atrocities in Belgium will be pity: pity for those who have lost loved ones, pity for those who are injured, whose dreams for the future are destroyed, pity for those who just happened to be in the wrong place at the wrong time. For policymakers, however, there are other aspects. The list of terrorist incidents is getting longer and, quite apart from deciding how best to protect against them, governments will need to think through broader implications. What effect will they have on public attitudes?
In Britain we have been here before. The IRA's bombing campaign which lasted through much of the second half of the last century became part of the backdrop to our lives; Airey Neave MP, war hero and close confidant of Mrs Thatcher, blown up in his car; Norman Tebbit's wife crippled in the Brighton bomb that was intended to eliminate the Conservative cabinet. Bombs in Hyde Park, in Harrods, in Bishopsgate, at Canary Wharf, and watchful eyes on the tube for anyone walking away from their luggage.
This time it will be different. It is much harder to spot a suicide bomber then to notice that a package is unattended. An enemy who is prepared to die is more dangerous than one who is not. But, against that, surveillance is much more sophisticated now and machines will be able to do much of what was done by the public in the 1970s and 1980s. Anyway, the idea of civilians being targeted indiscriminately is not new to us. A generation further back, German rockets dropped from the sky entirely unpredictably. No amount of vigilance could really do anything about it. The country simply put up with it doggedly because it had no choice.
So what are the likely political consequences of this campaign for the UK? Will it persuade the public that we should drop our involvement in the Middle East? Will it make us less tolerant of immigrants or of our own Muslim population? Will we turn to the extremists of the right or of the left and become more insular? Perhaps Isis in their desert fastnesses think or hope so but, if that is the case, they are likely to be disappointed. I cannot answer for other European countries because I don't know them well enough but, having lived here through the IRA campaign and through the mayhem of 7/7, I have no doubt that if something happens in London we will meet it as phlegmatically and as practically as we did before.
Yes, security will tighten. Yes, there will be less tolerance of hate-preaching. But those things aside, the reaction from the British people, from all parties, including all those immigrants who have chosen to come here and adopt our way of life, will be, as it has always been, to stiffen the sinews, face into the wind and doggedly keep going down those paths which we believe to be decent and right. It is what we do and it is also the reason why we all have the right to be proud of being British.