A tipster who supplied a story to the Sun about the death of a prisoner in solitary confinement at a Category A prison may have been pretending to be a prison officer, a court was told today.

William Clegg QC, representing Sun reporter John Troup, told Kingston Crown Court that the informant who supplied information about the death of hitman David Croke may have lied about his occupation to obtain a furtive cash payment.

A newspaper tipster might want to receive cash rather than an electronic payment into their bank for several reasons, including keeping their role or windfall secret from their family or from the Benefits Agency, the barrister told the jury.

At the Sun corruption trial, Mr Troup, the Sun’s former East Anglia reporter, is charged with one count of conspiring to commit misconduct in public office over a story about Croke’s death at HMP Whitemoor in Cambridgeshire in 2007.

After the story’s publication, Mr Troup emailed Graham Dudman, the Sun’s then managing editor, telling him that a cash payment for the story was necessary because the source was a prison officer who was worried about being detected.

The prison officer knew that the Home Office monitored the bank accounts of prison officers, Mr Troup warned his boss.

Making his closing speech, Mr Clegg, for Mr Troup, stressed that his client now realized that he wrong to have stated in his initial defence statement that he had written the story.

Subsequent to that initial statement a Ministry of Justice press office log showed that his colleague Simon Hughes had stood up the story, which Mr Troup now accepted.

Mr Clegg asked the jury to consider what evidence there was that the tipster who supplied the story to the Sun was actually a prison officer, which would make him a public official banned from selling confidential information without good cause.

Mr Clegg pointed out to the jury that it was agreed that the Home Office did not monitor the banks accounts of prison officers to see if they were being selling stories to the papers.

He said: “Looking at this email we know that the tipster has lied to John Troup because it says he, the tipster, claims to John Troup, that the Home Office routinely monitor the bank accounts of warders at Category A jails.

“That was a lie. The tipster was telling John Troup a lie. It was a lie told to get his money in cash.”

The QC continued: “What else did the tipster say? I am a prison officer. Well, that may also be a lie.”

He told the jury: “And if it is, that man in the dock is not guilty.”

Mr Clegg said: “The prosecution hinges on the tipster telling he truth about his occupation – but lying in the next breath about whether his bank account is monitored by the Home Office."

He objected to the Crown’s description of tipsters receiving “wheelbarrows of cash” from the Sun.

“Let's be straight,” Mr Clegg said. “The only payment of all the years John Troup worked for the Sun was a payment of £300; that's not going to need a wheelbarrow, not even the small one by my grandson's hoping to get for Christmas.”

While the Crown alleged cash payments to public officials were necessary to land exclusive stories, Mr Troup had managed to find stories aplenty in his newspaper career, including an agenda-leading investigation about alleged match-fixing by the Liverpool goalkeeper Bruce Grobbelaar.

Mr Clegg said: “He worked for the Sun for approximately 6,000 days. If you look at Count 8, his alleged criminality is alleged to cover 16 days. The other 5,984 days there’s no suggestion, no allegation, that he's done anything illegal or improper at all. Quite the reverse.”

Concluding, the seventh of the seven closing speeches, Mr Clegg told the jury it had been “a long and memorable trial.”

He went on: “And what an odd trial it is: no-one has died, no has been attacked, no one has had anything stolen – but a fortune of our money has been spent prosecuting these newspaper men for publishing the truth.”

The Judge, Richard Marks QC, told the 12 men and women of the jury that they had been privileged to hear “exceptionally well-argued” closing speeches from “amongst the finest in the criminal bar."

Court adjourned until 5 January 2015, when Mr Justice Marks is scheduled to begin his summing up.

Mr Troup, Mr Dudman and four other defendants – Chris Pharo, Ben O’Driscoll, John Edwards and Jamie Pyatt – deny conspiring to commit misconduct in public office.