The couple and four others were taken to separate police stations yesterday as the police investigation into alleged phone hacking at the tabloid newspaper stepped up a gear.
News International, Brooks’ former employer, confirmed that head of security Mark Hanna had also been arrested, along with another non-editorial member of staff, whom the company is not naming.
Five people understood to include the couple were released on bail last night, Scotland Yard said.
Operation Weeting, which was launched by the Metropolitan Police in January in response to the phone hacking scandal, has now seen 22 people arrested. However, yesterday’s raids were its single biggest swoop.
It is the second time Brooks has been arrested in connection with the inquiry, although last time she was allowed to report voluntarily. It was the first time her husband had also been taken in for questioning.
On Sunday evening, Mr Brooks had written in the Telegraph: “The happiest moment of my year is about three hours before the first race at Cheltenham on Tuesday.”
However, those hopes were dashed as he was instead taken to a Buckinghamshire police station to be interviewed. Meanwhile, his wife, 43, was taken to a station in Oxfordshire.
Brooks, who resigned as chief executive of News International in July last year, was already due to answer bail later this month after being questioned by detectives last summer on suspicion of phone hacking and corruption.
The dawn raid on her home is potentially embarrassing for Prime Minister David Cameron, who was forced to make further admissions earlier this month about the extent of his relationship with the Brooks.
After it emerged that Scotland Yard lent an ex-police horse, Raisa, to the former newspaper editor, the Prime Minister conceded it had been among his mounts on rides with Mr Brooks – a friend from their Eton school days.
Officers from Operation Weeting said they consulted the Crown Prosecution Service before carrying out yesterday’s raids.
The force said searches were taking place at several addresses after a 39-year-old man was arrested in Hampshire, a 46-year-old man was held in west London, a 38-year-old man was arrested in Hertfordshire and a 48-year-old man was detained at a business address in east London. All six were interviewed at separate police stations.
The arrests, which are not understood to result from information passed to them by News Corporation’s management and standards committee, come just days after Brooks’s lawyer Stephen Parkinson said evidence given by Metropolitan Police deputy assistant commissioner Sue Akers at the Leveson Inquiry brought “much prejudicial material” into the public domain.
Brooks’ relations with top police officers and politicians were called into question in recent weeks after it emerged she “fostered” Raisa when it retired from active service in 2008.
She paid food and vet bills until Raisa was rehoused with a police officer in 2010, months before fresh investigations began into illegal activities at the News of the World.