An Old Bailey judge told a jury today they had to decide if a journalist paying a civil servant for information was in the public interest or a commercially driven "corrupt relationship," noting that: "the fact that a journalist thought a story was in the public interest is not a defence to this charge."

His Honour Judge Rook was summing up the case at the end of the three week trial of Sun Westminster correspondent Clodagh Hartley, who is charged with conspiracy to commit misconduct in a public office after paying an HMRC press officer over £14,000 for information, including advance details of the 2010 budget.

Counsel for Hartley has told the court that her source, Jonathan Hall, was widely known amongst senior managers at the newspaper and at no point did anyone tell her: "you should stop doing that." Emails between senior Sun staff given to the jury contained an instruction to Hartley to remove Hall's name from the News International computer system as he was an "important source."

The judge then directed the members of the jury that to find the reporter guilty they would have to be sure that she knew that the civil servant's conduct was so serious as to amount to a significant "breach of the public's trust." The prosecution has argued that Hall, who was in charge of media relations for HMRC's law enforcement desk was driven merely by greed and ended up in the position of having: "two paymasters," the taxpayer and News International.

During the course of the trial the jury has also been told about a culture of "bullying" at the Sun, with documents shown to the court about a successful claim of harassment taken out by Hartley against a senior member of the newspaper's staff who the journalist testified she was "terrified of." Also on trial is the civil servant's partner Marta Bukarewicz who had large sums of money from News International paid into her bank account before transferring them to the civil servant.

Both of the accused deny the charges. The jury is expected to retire and consider its verdict on Monday afternoon.