We live in dangerous times.
Air travel is vulnerable. Our threat level is designated severe. We are warned to remain vigilant and report anything untoward on trains, buses and in public places.
And the bleak truth is that the discovery of explosives hidden inside printer toner cartridges two weeks ago, would not have happened without information passed on by Saudi Arabia.
Anyone who heard Sir John Sawers - ‘C’ to James Bond aficionados – speaking last week will know that MI6 does not condone or practice torture. Nor, according to his MI5 counterpart, do they.
These are worthy sentiments. Yet I cannot help wondering whether the Saudi Arabians - not noted for their democracy or human rights - would have the same scruples.
Imagine, if you can, the horror that a ‘dirty’ bomb would inflict on any of our great cities. Think of countless deaths, both immediate and more slowly, through radiation. And then envisage a vast conurbation left deserted for the hundreds of years it takes for radiation to decay to a safe level.
If putting pressure on an informant can save the lives of tens of thousands, do his or her human rights outweigh those of their intended victims? Where do you draw the line?
And if it will save lives, should we accept evidence gained through torture?
Certainly, our Foreign Office admitted this week that we would, after former US President George Bush alleged that ‘waterboarding’ during interrogation broke plots to attack Heathrow and Canary Wharf. Even Churchill and Roosevelt joined forces with Stalin in order to beat the Nazis. To them, the greater good outweighed his crimes against his people.
The work done by our security services is of necessity, secret. Snug in our comfortable homes in our democratic country with our legal rights, we do not have to think – much – about what is done in our names.
These brave men and women operate, of necessity, in a murky world behind the scenes. Like the SAS, their heroics are better unpublicised, for good operational reasons.
For those same reasons, I wish that Sir John had not chosen to step out of the shadows - the first head of MI6 to do so in 101 years. The mystique is broken.
We must believe in those we have entrusted with our safety and allow them to remain secret.
For me, it is enough to know that they are there.