Controversial surveillance technology that indiscriminately harvests information from mobile phones is being used by at least seven police forces across the country, a far larger number than previously known, according to police documents.

The hardware, known as an IMSI catcher, tricks mobile phone handsets across an area of several miles into connecting to them by impersonating cellphone towers, and can be used to pinpoint phone owners’ locations or intercept phone calls and text messages.

The Metropolitan police were previously known to have purchased IMSI (international mobile subscriber identity) technology. However, documents obtained by the Bristol Cable, a citizen’s media cooperative, indicate that at least six other police forces have bought the same hardware, also referred to as CCDC (covert communications data capture).

Police refuse to acknowledge their acquisition of this technology or discuss how they use it, claiming that any disclosures could assist criminals and terrorists. As well as the Met, other forces understood to be using it include West Mercia, Warwickshire, West Midlands, Staffordshire, Avon and Somerset, and South Yorkshire.



Matthew Rice, an advocacy officer at the campaign group Privacy International, said: “IMSI catchers, by their very nature, operate indiscriminately, gathering information from all individuals in the particular operating area. This collateral intrusion into the private lives of many innocent individuals is deeply concerning in any context let alone one that is, almost deliberately, opaque.”



Civil liberties campaigners have criticised the lack of accountability surrounding IMSI catcher use by police. Rice said the continued secrecy “shuts down debate in the worst way. Policing by consent requires that these evolving techniques be discussed openly and robustly in society, otherwise there is no way of giving true and informed consent”.



The technology works by exploiting the fact that mobile phones constantly seek the strongest possible signal in order to make and receive calls and data. IMSI catchers present themselves as the strongest signal in the area, prompting all nearby mobile phones to connect to them.

The technology then routes the signal to a normal mobile mast, allowing the phones to continue to function, albeit with all the data potentially being scrutinised by whoever is controlling the IMSI catcher.

The use of the controversial hardware emerged after the Bristol Cable noticed that South Yorkshire police’s budget had allocated £144,000 for “IMSI covert communications” in 2014 and “CCDC” in the same document.

When asked, a press officer for the force said they were the same item, but refused to disclose any further information for operational reasons.

A Metropolitan police transparency document listing all contracts with suppliers agreed between October and December 2015 shows £1,037,223 allocated for “CCDC” to telecommunications firm Cellxion. A similar document for Avon and Somerset police shows a £169,575 payment to the same company for “CCDC equipment”.

Marketing documents published by Privacy International show Cellxion has previously touted an IMSI catcher as “a comprehensive set of tools to combat the growing use of mobile phone communications technology in crime and terrorism”.

Meanwhile, the minutes of a meeting between the police and crime commissioners of West Mercia and Warwickshire police reveal their approval of a plan to purchase a replacement for their current CCDC deployment, in part on the grounds that neighbouring forces were also using the technology.

“Within the West Midlands region both West Midlands and Staffordshire police have recently purchased and operated 4G-compatible CCDC equipment,” the minutes state.

“The purchase [of replacement CCDC units for West Mercia and Warwickshire forces] would allow the use of the equipment in support of regional operation, but more frequently in support of local high-risk investigations, reducing the impact of demand across the region for the same equipment being used in West Midlands and Staffordshire.”

The West Mercia police and crime commissioner, John Campion, said: “I have seen real-life examples of the difference this technology can make in protecting extremely vulnerable people in our society. It is absolutely appropriate that the police can make use of this technology in order to keep people safe.

“It is very important to me that civil liberties are upheld and respected. I am reassured on behalf of our local communities that the safeguards and processes in place will ensure this technology will be used appropriately and proportionately.”

Matthew Ellis, the police and crime commissioner for Staffordshire, said: “It is right that police have the tools to tackle the complex nature of crime in the 21st century. Some tactics police use to keep people safe and bring criminals to justice can be intrusive and it is crucial that there are robust safeguards, framed by legislation, around this work, and there are.”

A spokesperson for the Metropolitan police said they “cannot comment on any specific surveillance methods or technology deployed to ensure the safety and security of Londoners. We will only use any surveillance methods or technology within the parameters of the legislation and associated governance and oversight regimes.”

The Warwickshire police and West Mercia police temporary assistant chief constable, Stephen Cullen, said: “Our main priority is to protect the public from harm and we achieve this by utilising a number of techniques, some of them covert in nature. To retain their effectiveness we are not able to openly discuss these methods.”