Rebekah Brooks and the police 'gift' horse

Scotland Yard faces further questions about its relationship with News International after it emerged Tuesday that it had lent a police horse to Rebekah Brooks when she was editor of The Sun.

Mrs Brooks was one of only 12 people allowed to adopt a retired Metropolitan Police horse in 2008, the year after two people were jailed for phone hacking at her former newspaper, the News of the World.

She passed a vetting procedure after officers from the Metropolitan Police's Mounted Branch visited her home in the Cotswolds, where she is said to have gone riding with the Prime Minister.

Although the Met routinely lends retired horses to charities and members of the public, who pay for their upkeep, one MP suggested the arrangement was more evidence of the "intensely close relationship" between the Met and NI executives.

David Wilson, Mrs Brooks's spokesman, said Mrs Brooks had ridden the horse, though the Met's website says it is looking for retirement homes "where the horse will not be ridden".

A Met spokesman was unable to explain the apparent discrepancy. The unlikely twist came a day after the Leveson Inquiry heard that the relationship between the Met and NI was "at best inappropriately close and at worst corrupt".

At the time Mrs Brooks took on the horse, she was editor of The Sun, but had given evidence to a committee of MPs five years earlier admitting that the News of the World had paid policemen when she was editor of the Sunday paper between 2000 and 2003.

By the time she gave the horse back to the Met she was chief executive of News International and the Met was facing calls to reopen its investigation into phone hacking following the disclosure that thousands of names of potential victims appeared in notebooks seized from the private investigator Glenn Mulcaire.

On Monday, the detective leading investigations into phone hacking and corruption disclosed that a mole had briefed Mrs Brooks on the original investigation into voicemail interception in 2006.

Tom Watson, the Labour MP who has been at the forefront of Parliament's attempt to uncover wrongdoing at News International, said: "In the light of the serious revelations at the Leveson Inquiry this week, the saga of the horse may seem trivial, but there is a serious question here of who authorised the loan of the horse and whether it cost any money.

"It is yet further evidence of the intensely close relationship between executives at NI and the Metropolitan Police."

The issue of "horsegate", as it was called on Twitter, was even raised at Downing Street's daily briefing for lobby journalists. Asked whether David Cameron, a friend and neighbour of Mrs Brooks, had ridden the horse, the Prime Minister's spokesman said that information was not available to him.

Lord Blair, who was the Metropolitan Police Commissioner when Mrs Brooks took on the horse, said he was unaware of the loan. Each year around 10 of the Met's 120 horses retire from working life.

Mrs Brooks, who is married to the former racehorse trainer Charlie Brooks, kept the horse at her farm in Chipping Norton until 2010. It was then found a home in Norfolk with a serving police officer, and has since died of natural causes.

A spokesman for Scotland Yard said: "In 2008 a retired MPS horse was lent to Rebekah Brooks. The horse was subsequently rehoused with a police officer in 2010."

Yesterday, the Leveson Inquiry into press ethics was told by Simon Hughes, the deputy leader of the Liberal Democrats, that The Sun derailed his chances of becoming party leader by obtaining telephone records revealing he had used a homosexual chatline.

Mr Hughes, who was odd-on favourite to win the leadership election in 2006, said his poll ratings plummeted after The Sun published an article in which he was forced to admit he had relationships with both men and women.