The wonderful thing about this interaction – the one that's going on right now between you and me – is that, unlike email, Twitter or social networking, no-one can spy on it.

The government says it wants greater rights to look at our email and sites such as Facebook, but what's going on in your brain right now as you read this newspaper is something the authorities cannot reach. You have circumnavigated the technology. You are a radical.

Whether we will be able to say that in 10 years, or five, or even next year is another matter. That's the thing about surveillance and spying, as the BBC's new series on the subject, Modern Spies (BBC Two, Monday, 9pm), pointed out: there is always technology making new things possible. Who we want to spy on has also changed – our enemy used to be Russia. Now it is someone who was probably born in Britain.

Among other things, Modern Spies explored the effect this has had on recruitment. This used to be done at top universities, but the gentleman spy with a first from Oxford would be absolutely no use these days among the working-class Muslim communities in Britain where much of the threat is perceived to lie.

Shami is an example of the new kind of agent that has emerged: a British, working-class Muslim who can become part of the communities being targeted by MI5. Shami told us his job was to be a Mr Grey, the kind of person you would forget in a second, and that his biggest fear was missing the vital piece of information.

The programme's biggest surprise was one that it explicitly set out to exclude. Right at the start, the commentary said the real world of spying was nothing like the fictional one of Bond, Bourne and Smiley. It's not like that, they said.

"If James Bond worked in MI6 today," said one agent, "he would spend a lot of time behind a desk doing paperwork."

But then, as we got further into the programme, we discovered that, in some ways, it is exactly like that. There are just as many Russian sleeper cells in America, for instance, as there were at the height of the Cold War and we have similar operatives over there. We also saw FBI surveillance footage of one Russian agent handing an envelope to another on a park bench in Washington. The park bench has always been the setting of choice for spies and, in some cases, still is. That was reassuring.

What has changed is that this more old-fashioned work is now part of a bigger picture that includes cyber-spying (like almost everything else, a lot of spying has been forced to go digital). What hasn't changed is the motivation for the work. Shami was asked why he chooses to be a spy. It's exciting, he said, but mostly because I can prevent the loss of life.

I have no idea if this really is why Shami does the job but it is certainly at the heart of why we need spies. There may have been some spectacular failures of intelligence in recent years – Iraq being the most obvious – but what Modern Spies showed is that a modern mixture of cyber geeks and more traditional sleepers are still doing the job they've always done: sorting out what we know from what we don't from what we think with the ultimate aim of protecting us from what we fear.