Government leaks are the "lifeblood" of political journalism in Britain, media commentator Roy Greenslade (pic: The Guardian) told the trial of a Sun reporter today.
The Guardian blogger and City University professor was called in the defence of Whitehall editor Clodagh Hartley, who is on trial for paying a government press officer £17,000 for leaked information over three years, including advanced details of the 2010 Budget.
Greenslade told jurors at the Old Bailey: "There was once a case when political reporting was sitting in the Commons and taking notes. The way now is to cultivate sources. The cultivation of sources is really the job of the journalists.
"There would be no political journalism at all without leaks. Leaks are the lifeblood. The cultivation of sources in order to get leaks is how journalism works in this country.
"Obviously a source wants to give you information or can be encouraged to give you information in return for something else. It's a contract.
"Some people will do it because they want to make mischief, for a lunch and a drink, for political advantage. Some will do it in order to receive a favour – perhaps they can get a leg up somewhere – and some will do it in return for money."
He went on to say journalists cultivate sources from "bottom to the top", the most important being the ones closest to government information.
He explained there had been a rise in media management strategy, where government employs more and more press officers and special advisers – or spads – to control the flow of news and present it in the best possible light.
He said this led to "daily arm-wrestling between the press and the government as to what information is released and which information is squeezed out of government".
The job of the journalist was to "get to the truth" and always question whether they are "suffering from spin".
While the Freedom of Information Act was introduced for more openness, government had also devised a strategy to control information.
For example, the court heard that during the 9/11 terror attacks a special adviser sent an email saying "this is a very good day to get anything out we would want to bury".
Greenslade said the government used a variety of tactics, through embargoes, press releases, and briefings of selected journalists.
He cited Damian McBride's book Power Trip as an example of a special adviser using his position to show his political master – Gordon Brown – in the best possible light.
Earlier in her defence, Hartley, a mother of two, told the court that there was a "massive public interest" in running a story with details on the 2010 Budget before it was subjected to "spin".
Hartley, 40, of Brockley, south east London, denies conspiracy to commit misconduct in public office along with Marta Bukarewicz, 45, of Kentish Town, north west London, who is the girlfriend of HM Revenue and Customs press officer Jonathan Hall.
Greenslade has worked for a number of newspapers, including the Sun, the Daily Mirror and Daily Star, since beginning his career in the 1960s.
The trial was adjourned until today when closing speeches are expected to begin.
Email pged@pressgazette.co.uk to point out mistakes, provide story tips or send in a letter for publication on our "Letters Page" blog