There is on the drawing board a device which automatically processes live pictures from closed circuit cameras and, from the body movement, sounds an alert when it detects that someone in the picture might be about to commit a crime.
While the new film Minority Report portrays a future where people are arrested before they commit crimes - the reality is that advances in genetics, and the processing of personal data, and, yes, CCTV are opening up some of those possibilities in the present.
But a dilemma comes with them: should people be incarcerated because of something they might do?
Our Science Editor Susan Watts reported.
It sounds like science fiction, that one day we'll have the technology to stop a murderer before they've even finished planning their attack. But reality is catching up fast. Fiction is becoming fact.
The police can get there beforehand and can prevent anything happening.
PROFESSOR PETER TYRER:
The possibility of that sort of tragedy being prevented is possible.
PROFESSOR PETER McGUFFIN:
I think it might predict those who are at high risk of behaving badly.
Set some 50 years in the future, the film turns around Tom Cruise's troubled detective from the department of "pre-crime". He taps into the visions of three "pre-cognitives", who visualise murders ahead of time. Minute examination of what they see allows him, and a squad of jet-packed super cops, to catch a crime before it happens. He wants to rid the world of crime.
It's an interesting dilemma, because they are able to predict a murder before it happens. You can be arrested and sent away without ever having committed a crime.
So how close are we today to a world where such pre-emptive policing might be possible? Part of the answer might lie in a canal boat on the Thames. This man is working with CCTV videos to see whether the way you walk reveals if you are about to commit a crime.
Here she starts walking in a very aggressive and strong sort of way. Most people say it's that aggressive gait that is the most predictive element in that clip.
He's building a software system that mimics the clues people use to work out if certain individuals are about to do something wrong. If it was connected up to a CCTV network, it could act as an early warning system for police pre-crime.
The police are keen to do it this way. If only we can provide them with the tools necessary to spot it in time. Remember also that if we're in the game of predicting then there are no criminals. Nothing has happened yet. If, by deploying a police van within a few yards of the incident the incident never happens then it really doesn't matter whether it was going to be a criminal incident. In other words if you can prevent crimes, there are no criminals.
In the film Tom Cruise raids computer stores of clues about where people live to track down potential murders, and even now similar geographical computer systems are under trail in Britain's police departments.
PROFESSOR JOHN MACINTYRE:
What we can do is predictive stuff that allows the police to see where potential repeat victimisation, in terms of burglaries, will occur. They can target particular physical locations, properties and areas, and also particular offenders. They can see who is the most likely person to have committed a particular crime. They can target their resource in that way as well.
Scientists exploring links between our genes and our behaviour are developing tests to spot those of us whose DNA might mark us out as future murderers.
I'm pretty sure that within the foreseeable future we'll be able to identify genes that contribute to the risk of anti-social behaviour. They should be fairly straight forward things to test. If we identify a gene that might make someone more susceptible to a certain kind of behaviour, it doesn't mean they're actually going to do it. It means that we can perhaps even identify the sorts of environments that might make them more likely to carry out those unwanted types of behaviour, and stop them doing it.
Technology to predict crime, and perhaps prevent it, is pretty much here, or soon will be. Which leaves only the decision of just how far we want our police forces to go? Are we happy with a world of constant, intimate surveillance? Perhaps so if the trade-off for a little loss of liberty is a near zero crime rate.
I'd forgotten how many there were...
In the film those arrested float in suspended animation. In real life, the Government wants to close a legal loophole so those of us who behave dangerously, yet have no treatable mental illness, can be locked away to protect society from what we might do. Peter Tyrer is advising on how a potential new law might work.
I still remember very clearly someone who told me he was thinking of killing his father. I felt there was a very strong risk of that. I could do very little apart from contacting the police and saying I'm very concerned this man is making a threat which could be acted on. I also got in touch with the father and suggested that he ought to take some sort of avoiding action. The father felt he couldn't leave his house or do anything special to avoid this, a week later the patient killed his father. I think if this legislation were enacted the possibility of preventing that sort of tragedy is possible.
Do you get any false positives?
The problem is how many wrongful detentions you might maker. The concern is the Government's latest moves might be rushed in to quieten an uneasy public.
There's a political imperative here that goes ahead of the science.
We're talking about predetermination which happens all the time. Why did you catch that?
Because it was going to fall.
You're certain? But it didn't fall, you caught it. The fact that you prevented it from happening doesn't change the fact that it was going to happen.
Perhaps science will one day do more than bring us technological marvels, and create reliable tools to mete out the tougher justice the public now demands, instead of just convincing a jury after a crime has taken place.
This transcript was produced from the teletext subtitles that are generated live for Newsnight. It has been checked against the programme as broadcast, however Newsnight can accept no responsibility for any factual inaccuracies. We will be happy to correct serious errors.