A jury at the trial of four Sun journalists has heard that a civil servant accused of leaking information to the newspaper had the highest possible security clearance. Belinda Vern the former head of the army's secretariat testified that one of her senior staff, Bettina Jordan-Barber had been subject to "developed vetting" so she could access the information she needed to brief government ministers about military matters. The prosecution say that civil servant received £100,000 for giving stories to reporters at the tabloid newspaper while it was being edited by Rebekah Brooks.

Asked about the impact of unauthorised information being given to the press, which was often about issues of sexual misconduct the civil servant said it could "prejudice disciplinary investigations and lead to a "loss of confidence in our department and in the Ministry of Defence generally".

However cross-examining the witness Trevor Burke QC, who is representing senior Sun journalist John Kay, raised a story about female army recruits allegedly suffering sexual harassment asking "Your hope was that the press would never find out about this" and argued the story was clearly in the "public interest".

Burke told the jury that the wars in Iraq and Afghanistan led to increased press interest in army matters and that the "public right to know what is happening in a war zone," adding that the press and media had a duty to "hold the government to account".

The defence barrister also suggested that it was well known that The Sun was "the favourite paper in the army". A statement he later amended after being, "’court martialled’ by the judge" to "The Sun describes itself as the forces favourite paper".

As well as Kay also in the dock are the paper’s deputy editor Geoffrey Webster; executive editor Fergus Shanahan; Royal editor Duncan Larcombe and an army officer and his wife, John and Claire Hardy.

All of the defendants deny all of the charges, the trial continues.