So far in this century, I would suggest that governments have got this pretty right.
They have provided lavish new funding for MI5, MI6 and, above all, GCHQ.

They have backed electronic surveillance, which some foolish libertarians denounce as the machinations of a police state, but which represents our first line of defence in detecting terrorists.

I have visited GCHQ’s headquarters in Cheltenham and roamed its gigantic underground level, where hundreds of computers churn 24/7, monitoring data and keywords from countless millions of phone conversations and internet communications.

Libertarians such as The Guardian newspaper find such scrutiny intolerable, but I — and probably you, too — are more than happy to have my own phone conversations tapped as the price of empowering our spooks to pinpoint such a man as who carried out yesterday’s savage killings.

It is too soon to know if he was already known to the Security Services, but we must recognise the impossibility of tracking, far less detaining, all those who show an interest in extremism or even terror.