Nearest equivalent would have been some of the IRA bombings, like the Birmingham one (leaving aside bombings in the German war which killed far greater numbers). Most people in Britain would very likely have preferred to see the people found guilty hanged for it. Of course it later turned out that they were not in fact guilty.

The possibility of killing someone who is in fact innocent is one reason for being against judicial killing, but only one reason. Being locked up for years for a crime you didn't commit is such a terrible thing to happen it might even be felt as worse than being killed. Having a situation in which innocent people are not found guilty is obviously what really matters.

But even if it were impossible for those kind of things to happen, I believe that the damage done to society by having judicial killing is so great that it can never be justified. I think it probably actually increases the murder rate, and I have never seen any research that indicates the reverse. And even aside from that, I think it damages children growing up in a society that does that kind of thing.

That's why I rejoice in the evidence from this referendum in Ireland that in at least one country it now seems that this is a view shared by most people. (And a country which in many ways is fairly "conservative".)