Woman and three teenagers arrested over M&S, Co-op and Harrods cyber attacks

Four people have been arrested by police investigating cyber attacks targeting M&S, Co-op and Harrods.

A 20-year-old woman and two males, both aged 19, and another aged 17, were detained in London and the West Midlands as part of a National Crime Agency (NCA) operation. They were arrested at their homes on suspicion of Computer Misuse Act offences, blackmail, money laundering and participating in the activities of an organised crime group.

Money blog: Cost of renting over owning home is a lot Electronic devices were seized from the suspects and are currently being analysed by forensic experts. M&S halted online orders, and shelves were empty in shops after the cyber attack on the retailer earlier this year.

The initial hack into the retailer's systems took place in April through "sophisticated impersonation" involving a third party. Disruption is expected to continue at the retailer until the end of this month.

The Co-op and Harrods were also subsequently targeted by hackers. Paul Foster, head of the NCA's National cybercrime unit described the arrests as a "significant step" in their investigation, which remains "one of the agency's highest priorities".

He added: "Our work continues, alongside partners in the UK and overseas, to ensure those responsible are identified and brought to justice." The arrests, which took place early on Thursday morning, were supported by officers from the West Midlands regional organised crime unit and the East Midlands special operations unit. Earlier this week, the chairman of M&S told MPs that the hack had been "traumatic" and like an "out-of-body experience".

Archie Norman, however, refused to be drawn on whether the retailer had paid any ransom. "We are not discussing any of the details of our interaction with the threat actor, including this subject, but that subject is fully shared with the NCA," he said.

It is estimated that the cyber attack will cost M&S up to £300m this year. Read more:South West Water agrees to pay £24m for wastewater failuresRoyal Mail to scrap second-class post on Saturdays and some weekdays Days after M&S was attacked, the Co-op was targeted and forced to shut down some internal systems.

Harrods was then hacked, and also had to shut some systems despite its website and shops continuing to operate. Of those arrested, the 17-year-old British male and a 19-year-old Latvian male are from the West Midlands.

Another 19-year-old man is from London and the woman from Staffordshire. An M&S spokesperson said: "We welcome this development and thank the NCA for its diligent work on this incident." A Co-op representative commented: "Hacking is not a victimless crime.

Throughout this period, we have engaged fully with the NCA, and relevant authorities and are pleased on behalf of our members to see this had led to these arrests today.".