A senior military official who sold stories to The Sun newspaper had high-level clearance and access to top-secret documents, The Old Bailey heard.

The revelation was made at the trial of four journalists – two of them from Kent – who are accused of paying public officials thousands of pounds for information.

The court heard how Bettina Jordan-Barber, 42, was paid large sums by the tabloid while working as a strategy officer who briefed the defence secretary.

Jordan-Barber, who is not before the court and doesn't face any charges, was allegedly paid £100,000 by chief reporter John Kay for details she leaked to the paper and which resulted in a string of stories about army scandals.

"She was 'developed vetted', which is the highest level, I believe. I'm not a security expert but she was cleared to see information up to top secret level, not that we generally dealt with that in my team." - Jordan Barber's boss Belinda Vern

Belinda Vern, former head of the Army Secretariat, confirmed she had been Jordan-Barber's boss.

Prosecutor Mark Bryant-Heron QC asked Mrs Vern to explain Jordan-Barber's role to which she responded that she worked closely with the MoD press office and government and specialised in army discipline issues.

Mrs Vern said: "She was 'developed vetted', which is the highest level, I believe.

"I'm not a security expert but she was cleared to see information up to top secret level, not that we generally dealt with that in my team."

She added that her team were not authorised to deal with the press directly.

Cross-examining the witness, Trevor Burke QC, for Kay, asked Mrs Vern about a news brief involving allegations of a corporal sexually harassing two female recruits.

The brief stated 'the media are not currently aware of these allegations', the court heard.

Mrs Vern said 'sensitive information' would not be shared with the media, including the names of those being investigated by the Royal Military Police.

She confirmed to Mr Burke that in the case of the allegations against the corporal these rules served to protect him.

Mr Burke argued it fell to the press to expose such scandals and produced a story by John Kay, published in April 2006, which revealed the allegations.

The story read: 'The married corporal was said to have dropped his trousers and pants and "exposed his manhood" to the rookie.'

Mr Burke said it would have been evident the MoD was 'leaking like a sieve' and it would have been obvious The Sun had a source inside Mrs Vern's department.

She said she had no memory of an investigation into the source of the leak.

Mr Burke later told the court how Kay had written 454 military stories for The Sun, with '70-odd' relying on Jordan-Barber as a source.

He went on to ask Mrs Vern is she was aware of The Sun's close relationship with the forces, and the occasional MoD practise of handing exclusives to the paper.

Mrs Vern said she was only dimly aware of the practise.

Kay, 71, of Golders Green, London, denies conspiracy to commit misconduct in public office.

Deputy editor of The Sun Geoffrey Webster, 55, of Winchett Hill, Goudhurst, is accused of handing over thousands of pounds in bungs to public officials.

He allegedly authorised reporters to pay a total of £6,500 between July 2010 and August 2011. He denies two counts of conspiring to commit misconduct in public office.

The Sun’s royal correspondent Duncan Larcombe, of High Street, Aylesford, is accused of paying ex-Sandhurst Colour Sergeant John Hardy, 44, £23,000 for details about the Army base where Prince Harry trained.

The 39-year-old denies counselling and procuring misconduct in public office.

It is alleged Hardy funnelled some of the payments through his wife Claire.

Mr Hardy denies misconduct in public office, while Mrs Hardy denies aiding and abetting misconduct in public office.

The Sun’s executive editor Fergus Shanahan, 59, is also accused of plotting to pay a public official for stories, a charge which he denies.

The trial continues.