The UK data watchdog has announced a crackdown on rogue private investigators (PIs) after concerns have been raised over a number of "unlawful practices" including the use of computer hacking to obtain sensitive information.

"The work of PIs involves obtaining, handling and reporting personal information. As such they must comply with the Data Protection Act and be registered as data controllers. Our concerns are that some PIs are not following [the] rules," the Information Commissioners Office (ICO) said in a statement.

These so-called broken rules include maintaining records of personal information and "selling it to anyone willing to pay", hacking to obtain data, failing to register with the ICO and "blagging" to obtain personal information.

Additionally, the ICO said it received concerning reports about the use of surveillance and tracking devices by UK private eyes - who are also suspected of failing to give those snooped upon access to information stored about them. According to the office, which remains independent of the UK government, evidence has been gathered by its criminal investigation team that some PIs are misusing personal data and all those implicated will now be confronted.

"These are actions which may be in breach of the Data Protection Act," the ICO said. "Members of the investigation team will arrive unannounced, explain the reason for their visit and then investigate the concerns further."

IBTimes UK contacted a number of UK private investigation firms for comment. One that replied was London-based Research Associates. In response to the ICO crackdown, Paul Hawkes, an investigator and forensic consultant said: "As I understand the situation, the ICO routinely investigate rogue investigators who see themselves as 'information brokers', but tend to be referred to as 'blaggers'. It is likely that the ICO may be targeting the few investigators who remain outside of the Data Protection Act."

He added: "What some investigators remain ignorant of is the plethora of open source intelligence ('OSInt') now freely available to those who consistently educate themselves within the investigation industry, there are also exemptions to the Data Protection Act (specifically sections 35 and 29) that may be utilised to gather sensitive information within the limits of the current legislation. Clients may suggest non-legal ways of investigation, often due to their lack of knowledge of newer open source intelligence techniques."

IBTimes UK contacted the Association of British Investigators (ABI), a long-standing organisation that represents professional PIs in the UK, on 13 April, but received no response.

The term "blagging" gained popularity following the controversy surrounding investigations into corruption and unethical journalism at newspapers including the Murdoch-owned News Of The World. It revealed that a number of mainstream news outlets frequently employed PIs to aid in undercover investigations.

In one case back in 2012, private detective Philip Campbell Smith was one of four people jailed for illegally "blagging" private information for cash. As reported by The Guardian at the time, Smith, alongside Daniel Summers, Graham Freeman and Adam Spears, was caught in the middle of a "blagging conspiracy" where he used the shadowy technique to access confidential data for wealthy clients.