London's Metropolitan Police have admitted they had lent a horse to Rebekah Brooks, the former tabloid editor and top aide to Rupert Murdoch who was arrested over the phone-hacking scandal.

As the police force battles claims that it grew too close to Murdoch's British newspaper wing News International, of which Brooks was chief executive, a spokesman said she had provided a "suitable retirement home" for the horse.

"In 2008 a retired (police) horse was loaned to Rebekah Brooks. The horse was subsequently re-housed with a police officer in 2010," the Metropolitan Police Service spokesman said.

He added: "When a police horse reaches the end of its working life, Mounted Branch officers find it a suitable retirement home.

"Whilst responsibility for feeding the animal and paying vet bills passes to the person entrusted to its care at its new home, the horse remains the property of the Metropolitan Police Service."

Brooks's spokesman also confirmed the deal. "It was a charitable deed by Rebekah for a horse that would otherwise have been sent to the knacker's yard," he told AFP.

"It's well known in the horse-riding community that the police require homes for retiring police horses. Rebekah paid for its bills, paid for its food - and obviously rode it."

Brooks is known to be a keen rider, and her husband Charlie is a racehorse trainer.

The flame-haired Murdoch protegee has reportedly been a riding companion to Prime Minister David Cameron, whose constituency home is near Brooks in Chipping Norton in Oxfordshire, southern England.

The revelation comes a day after a government inquiry into media ethics heard that a Met officer gave Brooks, 43, extensive information on a criminal investigation into phone hacking at Murdoch's News of the World in 2006.

She was editor of the NOTW's sister paper The Sun at the time.

The Leveson Inquiry, set up after the hacking scandal closed the NOTW last July, also heard on Monday that The Sun had a "network of corrupted officials" including police who provided stories for cash.

Robert Jay, a lawyer for the inquiry, said the public were concerned that "the relationship between the police and News International in particular was at best inappropriately close and at worst corrupt."

Brooks, who edited first the NOTW and then The Sun before becoming head of News International in 2009, was arrested on suspicion of phone hacking and bribery in July. She quit the chief executive role but denies any wrongdoing.

- AFP