Are we any safer 10 years after the 7/7 attacks?
On the tenth anniversary of the London bombings, I keep hearing the same reflection: "7/7 feels like just yesterday".
I heard it on the Tube to work this morning, in the ITV Newsroom this lunchtime and at Scotland Yard this afternoon.
But for those tasked with preventing terrorist attacks in the UK, everything has changed.
MI5, Britain’s domestic security service, has grown vastly in the decade since 7/7. That rapid growth reflects a rise in the weight of its workload.
They have been forced to work in a different way - in fact, all the agencies whose job it is to keep Britain safe have had to break down their old silos and work together better.
And regional counter-terrorism units have been rolled out right across the UK. For them all, 7/7 must feel like a long time ago.
There have been many successes. Dozens of plots have been thwarted - last year, police officers made an arrest per a day for suspected acts of terrorism.
But are we any safer? Despite the fact that the authorities seem to be better at foiling plots, it is difficult to see how Britain is any less vulnerable to a terrorist attack.
The flow of extremists travelling to Syria and Iraq has been a disturbing, rapid and largely unexpected trend. It is only a year since so-called Islamic State declared a caliphate, and so the threat it poses to us is still a relatively new one.
Many people who work in the industry of preventing radicalisation speak of a national failure to understand the appeal of IS in many parts of urban Britain - the seductive simplicity of the biggest gang there is.
With hundreds of British citizens living under IS, including dozens of girls and several entire families, the perceived threat is evolving.
It makes for a far more confusing picture than the one faced by the security services of yesteryear, whose greatest challenge might have been thwarting crude IRA car bombs.
But here’s the paradox: although we seem to be less safe, the horror of 7/7 has not been repeated on British soil.
After today’s anniversary, we will reach another milestone tomorrow - the point when we can say that despite the fears of July 2005, Islamist terrorism in Britain has not claimed a single life in the last decade.