This, ultimately, is what it comes down to: risk and reward.

Today, surveillance and alarm technology has become cheap and plentiful. CCTV is everywhere. Bank vaults bristle with tracking devices, while our phones record us 24/7. The police can find you in Latvia using a pubic hair. And even if you get away, laundering money is harder than it has ever been. So why bother in the first place?

While none of the experts I spoke to thought it was impossible to get away with a heist, all believed it had become more difficult. In other words, the rewards don’t match the risks. “It’s very hard now,” says Simon Atkinson. “To actually undertake the heist itself is probably pretty easy, given enough intelligence to work through. But you’ve got to get away with it. You can’t just do a runner to the Costa Del Sol anymore. I think a proper criminal, for want of a better word, would say: ‘No, we can’t do this. We can’t get away with this.’”

The head of the City of London Police, Adrian Leppard, implied as much last year when he told the Telegraph that even organised crime syndicates were moving away from traditional crimes such as drug dealing towards more “low-risk, high yield” activity such as cybercrime. “Organised crime is motivated by money,” he said. “Whichever criminal activity delivers the most money, that is where they will go.” He estimated that around 25 per cent of British organised crime groups are now involved in financial crime.

Instead of one huge theft from a single well-resourced corporation, you can automate thousands of tiny thefts from ordinary people, many of whom will consider the loss too small and embarrassing to report. And you can forget the lengthy ordeal of fencing and laundering. A thriving anonymous market in stolen data allows the untraceable disposal of stolen goods via digital currencies such as Bitcoin.

Even if you are caught, the sentences are lighter: seven to ten years for even the most lucrative computer frauds, as opposed to fifteen to life for armed bank robberies. Many of these are not even that lucrative: a study in 2007 found that the average return from a British bank robbery was only £12,706.60 per person. “Criminals themselves seem to have learnt this,” the authors noted. As they used to say in east London, it’s just not worth it.

Cybercrime, on the other hand, is. “The heist definitely isn’t what it once was,” says Jim Stickley. “But that’s not because it’s impossible. It’s just, why put yourself at that kind of risk when you can steal digital information from anywhere in the world, and the chances of getting caught are so drastically reduced?

"If you’re in some small country where making two or three grand in a year is the best you can ever imagine, and you find out you can go online and rip off a company that makes hundreds of thousands of dollars in weeks, well, why wouldn’t you?” Robbery? “Leave that to the crackheads.”

This is a new world for British police. When computer offences were included in crime statistics for the first time last October, the overall crime rate soared by 107 per cent. The global cost of computer crime is estimated at £266 billion a year. Its anonymity and international scope often makes it impossible to find and prosecute the culprits (some of whom are working for foreign states). Instead, we are entering a preventative war in which governments must equip businesses and citizens to protect themselves. That will test all of us, and transform our idea of what crime looks like — leaving the "bad grandpas" of this world behind.

“I still think the physical heist is way cooler,” says Stickley. “It makes for much better movies. It’s not very exciting to watch a guy sit at a computer and type away for several hours. But the reality is that typing is far less risky and will pay off just as well.”

It doesn’t quite have the romance of Hatton Garden. But while the age of John Dillinger and the Great Train Robbery is over, a new, digital lawlessness has come into being which is every bit as lucrative. It has its own romantic myths, its own folk heroes, because as long as someone is getting away with what the rest of us can only dream of, the cult of the outlaw will stay alive — in whatever form it can.

Four more people will go on trial this February, charged with conspiracy to convert or transfer criminal property in connection to the Hatton Garden raid. Hugh Doyle plans to appeal his conviction.

You can read more in-depth features here and more from the Telegraph's comment desk here.