What if police could detect a crime before it has even happened?

Could nab a burglar before he’s broken a window, or stop a fight before the first punch is thrown?

It might sound like a fantasy; like a Minority Report-style piece of cinematic imagination, but the reality is that these things are being done all around you.

Mark Johnson is the head of analysis at Kent Police and it is his job to identify crime patterns and build intelligence for officers to use in operational duties.

Over the last three years, the 47-year-old has worked to help develop crime fighting technology across the whole county but his work didn’t begin in Kent, or even the UK for that matter, it started in Los Angeles, USA, back in 2012.

Mark and his colleagues had heard about a new computer programme that was drastically cutting crime in some of the most dangerous, underprivileged neighbourhoods of LA.

So with a healthy dose of scepticism, Mark’s colleague Deputy Chief Constable Paul Brandon, boarded a flight to the City of Angels to learn more about it.

On his return, the team – convinced the programme could work in Kent – immediately enlisted the help of American anthropologist Jeff Brantingham and began working with US-based company PredPol to tailor a system to be used here.

Mark is quick to stress the reality of using predictive policing is very different to Tom Cruise swiping a gloved hand through a 3D virtual reality computer screen.

“It’s a Google map on a computer screen and dotted on that map there are little red boxes – some as small as part of a road – that signal where a crime is likely to happen.

“Some of these predictive policing boxes will appear and disappear and then they’re boxes that don’t go away.

“The ones that don’t disappear mean longer-term issues, like it is covering a deprived area, or that location has a shop that sells alcohol to under-age kids,” he said.

Since the predictive policing programme was rolled-out in Kent in May 2013, low-level street crime, like common assault and anti-social behaviour, has dropped by 7%.

Mark admits it has not all been smooth sailing, with a number of the force’s officers dubious at the beginning: “There’s a thing called copper’s nose, which is the experience they have, the understanding they have, a sense when something doesn’t feel right, which a computer doesn’t have.

“Without good, old-fashioned policing it wouldn’t have worked. It’s 21st century technology meets old-fashioned policing.”

One incident that convinced a number of officers happened in Medway when the sergeant there asked his PCs to print off the map when they went out on patrol that evening and, when they had a quieter moment, to drive to the red location box nearest to them, even if their local knowledge told them it wasn’t one of the usual crime hotspots.

That night, in an area they would never normally go, officers found a mother and her child in the street who had both just minutes before been sexually assaulted. The suspect was arrested nearby later that night.

While Mark says cases like these are rare, it is a powerful example of what a complex computer algorithm can do: Lead coppers straight to a sex offender wanted by the Metropolitan Police.

As the technology gets more sophisticated, officers can make sure they are in an area before something has even occurred, their presence alone stopping even the most brazen criminal from striking.

PredPol technology uses three data points (past type, place and time of crime) to create a unique algorithm based on criminal behaviour patterns.

The PredPol software allows police forces across the world to tailor their system to their location.

When Kent Police began it’s predictive policing pilot in December 2012, it started by feeding in data, including five years’ worth of details of recorded crimes and three years of incidents of antisocial behaviour, into a computer.

Mark Johnson calls the PredPol programme akin to a “living thing” in that it must constantly be fed new information to keep being able to accurately predict where crimes will happen.

Kent’s PredPol system costs the equivalent of abour two police officers per year.

It is successful in predicting ‘space-dependent’ crimes, which are incidents that are linked to certain location, like anti-social behaviour and burglary, as opposed to crimes like murder or rape.