Detectives may need to fall back on “older ways” of catching criminals as encryption of technology becomes more of a problem, the head of Scotland Yard’s Flying Squad has said.

Organised crime gangs are increasingly sitting behind computer screens to steal from victims rather than risking arrest by staging armed robberies.

But the inability to crack encrypted devices and messages means investigators need to keep using tactics like going undercover and using informants to catch crooks, Detective Chief Superintendent Mick Gallagher explained.

“It might be that going forward we have to start re-establishing some of the older ways that we used to work and not be so heavily reliant on technology. If encryption for example is going to start causing a problem,” he said.

“We have to remain open so that we don’t resign past tactics and methods to the past. Sometimes it’s often worth revisiting something that worked very successfully.

“In the fast changing technological age that we’ve got at the moment it’s a challenge to keep up to speed with how things are developing.

“Part of our role is to make sure that we don’t throw the baby out with the bathwater when we’re moving forward organisationally with our tactics.”

Mr Gallagher spoke as the Flying Squad celebrates 100 years since it was first founded in 1918.

At the time the unit consisted of 12 specially selected officers and was led by Detective Chief Inspector Frederick Wensley, who had previously rescued a colleague from a shoot-out in the Siege of Sidney Street.

Known as the Experimental Mobile Patrol, the team had two horse-drawn covered wagons rented from the Great Western Railway, and patrolled the streets with detectives hiding inside, ready to pounce if they spotted a criminal.

Now the Flying Squad has 120 officers – soon to be 141 as its remit expands to deal with kidnap – and is best known for action-packed takedowns of armed robbers known by officers as a “pavement ambush”.

Key jobs in its history include the 1963 Great Train Robbery, when the squad arrested 17 of the 19 thieves responsible for the heist.

Police officers check the raided boxes in the vault of the Knightsbridge Safe Deposit Centre in 1987
Police officers check the raided boxes in the vault of the Knightsbridge Safe Deposit Centre in 1987 (PA)

There was also the infamous 1983 Brinks-Mat security depot robbery; the 1987 safe deposit raid in Knightsbridge; and more recently foiling a plot to steal jewels from a diamond exhibition at the Millennium Dome in 2000.

This was the biggest operation in Flying Squad history and stopped the robbery of the massive Millennium Star diamond, worth around £200 million, as well as a collection of blue diamonds.

The shattered case containing the Millennium Star diamond after the raid on the Millennium Dome in November 2000
The shattered case containing the Millennium Star diamond after the raid on the Millennium Dome in November 2000 (PA)

The squad, sometimes known as The Sweeney, also investigated the £14 million 2015 Hatton Garden safety deposit burglary.

Armed robberies remain the key focus for the unit, with moped smash-and-grab raids and deliberate gas explosions of cash machines both recent trends.

But Mr Gallagher explained that a number of crime gangs have moved away from armed robbery to other forms of crime.

“The better organised criminal groups tend to look at it as a business model and they will be looking at it from a perspective of ‘how much risk do I have to take to get a certain yield?’

“We’re seeing in London serious and organised criminal groups tend to graduate away from armed robbery which is a high risk and relatively low-yield, you will see them diversify into drug trafficking which is a slightly lower risk and a slightly higher yield. We’ve also over the last few years seen a further diversification into serious or complex fraud.

“The challenge is never-ending, they shape shift and we have to in order to meet that.”