Last week, in Westminster, marked the anniversary of the senseless attack on innocent civilians and the more purposeful effort to attack Parliament, in which PC Keith Palmer died in the line of duty.

In one sense, of course, this was a sad reminder of death and destruction – and a reminder, too, of the extent of our vulnerability to any form of terrorism that includes a willingness to commit suicide.

But, alongside these somewhat morbid and daunting thoughts, the anniversary reminds us also of something that is a permanent cause for hope and optimism. So far from destroying or even abating our democracy, this attack – like all its predecessors over many centuries – left Parliament functioning at the centre of Britain’s democratic system.

Neither bombs from the air, nor bombs placed in buildings, nor attempts at physical entry have been sufficient to dim the enthusiasm of Britain for its democratic institutions.

It is not an accident, but an achievement, that we are a country in which these institutions persist despite the many vicissitudes to which they have inevitably been subjected to over the course of their history.

It has been fashionable in certain quarters to ask whether the House of Commons really fulfils any important function in a democracy whose main concern is to elect and dismiss governments.

And I have to admit that I myself have occasionally wondered whether Parliament (as opposed to the electorate at large) really constituted any effective check on the executive in the age of the internet.

Whatever else Brexit has done or will do, the process of leaving the EU has given Parliament a new lease of life.