THE nature of investigating crime and prosecuting criminals is constantly changing and evolving.

Only 25 years ago it would have been unusual for police to arrest somebody with a mobile phone on them.

Now, most people – and, consequently, most criminals – walk around with the equivalent of a supercomputer in their pocket.

Whole lives can effectively be contained within these small devices – conversations, videos and pictures, details of the most personal nature.

On the one hand, this digital footprint can give police a helping hand in establishing, say, where somebody was at a given time, or whether or not they had been in contact with a particular person. On the other hand, the vast quantity of information means police have to be smarter than ever in their approach to investigations.

Chief Crown Prosecutor for Thames and Chiltern Adrian Foster is keenly aware of the challenges faced my police and lawyers when it comes to navigating this digital labyrinth.

“It’s a complex issue,” he said. “Phones now hold so much data on them. Even standard messaging and other communication has become encrypted.

“When the last guidelines were issued by the Attorney General, the average storage on a mobile device was 8GB. Now it is not unusual to have storage on 512GB on a phone with much more data available in a cloud.

“A download for one phone can be 30 to 40,000 pages long so to we need to use technology much better to search for evidence that proves whether an offence has occurred one way or the other.”

As well as becoming a component of a large volume of offences, technology is also right at the heart of many kinds of crime, and this trend doesn’t look like its about to end anytime soon.

Mr Foster continued: “I think cyber enabled fraud is probably the crime that is the most endemic at the moment, with people in all communities being affected but with the most vulnerable and elderly of our society being particularly targeted.

“These cases are difficult to investigate and prosecute as the perpetrators are often based abroad and the money is quickly taken out of the country but the area has the support of a specialist fraud division, which handles the very large and complex cases.”

While technology is being used more and more to commit offences, like fraud, harassment and stalking, police are able to use it to their advantage in the gathering evidence for criminal cases.

Mr Foster continued: “Its greatest weakness is that almost everything you do online leaves a footprint and is tracked. It can be used to pinpoint where you were and what you were up to at any given time.

“Cars are tracked via ANPR, phones ping off masts giving locations and even encrypted social media accounts can be searched for messages. All of this builds a picture which is easy for a jury to understand.”

Technology, according to Mr Foster, has also had an impact on reducing robberies, burglaries and car crime thanks to security improvements. But not all crime can be kept at bay thanks to technological advancements.

Other challenges faced by the police and CPS involve modern crimes that are staggering in ther audaciousness and violence.

Acid attacks, for example, were, just several years ago, a fairly minor phenomenon. Recently, their devastation has been felt across the whole country after a bombardment of news reports revealing their terrifying frequency.

County lines, a term that refers to drug supply links between major cities like London and Birmingham and county locations, is also on the rise.

The practice is particularly alarming because children and vulnerable adults are often exploited by gangs as part of the process.

Mr Foster said: “The use of acid and mopeds has begun to spread out from London as a means of assaulting and robbing individuals.

“Drug dealing now operates through a network of mobile phones which are used to order drugs across ‘county lines’ and which can be passed between organised crime groups.

“Police and prosecutors are targeting modern slavery offences, female genital mutilation and so called ‘honour’ based violence.”

Mr Foster, however, believes that the CPS – and indeed the police – are up to the task of maintaining law and order in the face of a rapidly changing world.

Because, while criminals evolve and develop new methods, the CPS too is consistently learning and bettering itself – ensuring it is equipped to face and prosecute the crimes of today. And the crimes of tomorrow.

“I am tremendously proud of all of my staff for their commitment and dedication, as they handle sometimes difficult and sensitive casework”, said Mr Foster.

“Our lawyers are supported by experienced business teams of paralegals and admin staff and our new recruits have settled in very well. However our inspectors recently highlighted two teams in particular: our specialist rape and serious sexual offence prosecutors and our in-house Crown Advocates, who present a large proportion of our cases before the Crown Courts with skill and professionalism.”

Mr Foster started his career with the CPS as a legal trainee barrister in 1993, becoming a prosecutor in West London. He moved to Gloucestershire as legal manager in 2002 and became chief there in 2006, before becoming national head of operations. He then became deputy chief in London before becoming chief in Thames and Chiltern in January 2014.