Prime Minister Theresa May told Parliament:
Yesterday an act of terrorism tried to silence our democracy. But today we meet as normal - as generations have done before us, and as future generations will continue to do - to deliver a simple message: we are not afraid. And our resolve will never waver in the face of terrorism.
London Mayor Sadiq Khan said:
We can’t allow them to succeed in dividing communities, we will not allow them to destroy our way of life. We’re going to be defiant, we’re going to be resilient, we’re going to return to work but of course never be complacent…we must never accept terrorists being successful.
Some of the calm reaction is good old-fashioned British stoicism. I think it also stems from an understanding there is very little that could have been done to prevent the attack.
The perpetrator appears to have been a single deranged individual with a car and a knife. He had a criminal record, but his last conviction was in 2003. He was known to have previously associated with extremists, but was not the subject of any active investigation.
The immediate vicinity of Westminster is one of the most heavily policed and secured areas in any major British city. Armed police reacted quickly; not quickly enough to save everyone, but it's difficult to see what more they could have done.
The police investigation is ongoing, and maybe it will turn up some additional understanding of the attacker's motives. But the fact is, we can't really stop an individual who one day decides to commit mass murder. At least it was not possible for the attacker to obtain guns, otherwise the death toll could have been much higher.
Can we stop the mindset which makes such crimes possible? Unfortunately this too is doubtful, especially in this day and age when hateful and murderous ideologies are just a few taps of the keyboard away.
We must try to build a society where we can live together in peace, prosperity, and freedom; in the end, this is the best way to discourage our fellow citizens from turning to hatred. We must be vigilant, and punish those who are caught planning or committing violent attacks; but sooner or later someone will get through.
When that happens, the most fitting memorial to the dead is to carry on living in a free and open society.