Former British prime minister Gordon Brown is giving evidence at the Leveson Inquiry as the investigation into media standards enters its most politically-charged week.
Chancellor George Osborne is also due to appear today while prime minister David Cameron will give evidence on Thursday.
Watch the Leveson Inquiry hearings live here.
Mr Brown said today he would defend press freedom even in instances where the press made mistakes. However he criticised newspaper coverage of UK involvement in Afghanistan.
He said "one newspaper in particular" had not taken on "difficult issues" but adopted the line that he "did not care" about British troops.
"What I think one newspaper in particular decided to do is it didn't want to take on the difficult issues," he said.
"It reduced coverage to 'we were doing something wrong'."
He added: "The whole focus of their coverage was not what we had done ... but that I personally did not care about our troops."
Mr Brown singled out The Sun for the way it had portrayed him on a number of occasions in relation to Afghanistan.
In one instance it said he had fallen asleep at a memorial for troops and claimed it was another example showing he did not care about the British forces.
"There's a story you fell asleep but you were praying and The Sun decides this is an example of someone falling asleep and dishonouring the troops," he said.
Mr Brown also raised a story published by the newspaper in 2009 after he misspelled a dead soldier's name in a hand-written letter of condolence to the victim's grieving mother.
Jacqui Janes accused the former prime minister of being "disrespectful" because the message began "Dear Mrs James" and appeared to contain other spelling errors and a visible correction to her son Jamie's name. The 20-year-old Grenadier Guardsman was killed by an explosion on October 5th.
Mr Brown has suffered with eyesight problems since a rugby accident in his youth.
He was reported at the time to have telephoned media mogul Rupert Murdoch directly to complain about the coverage he was receiving.
Mr Brown said the letter was used to show he had a lack of empathy, adding "and it goes on and on".
Mr Brown insisted The Sun had never given him much support, even before it switched its backing to the Conservatives in the midst of the 2009 Labour Party Conference.
He said: "It was suggested that somehow relations with The Sun or Mr (Rupert) Murdoch broke down because he decided he wanted to support the Conservative Party.
"The commercial interests of (Sun publisher) News International were very clear long before that and they had support from the Conservative Party."
He cited James Murdoch's 2008 MacTaggart lecture, describing it as "breathtaking in its arrogance and its ambition."
In the lecture, Mr Murdoch advocated controversial changes to British broadcasting including scrapping the impartiality requirement.
"We could not go along with that sort of agenda," Mr Brown said. "But while we resisted that we were not supported...
"The Conservative Party supported every one of the recommendations made by the Murdoch group."
Discussing The Sun's 2006 story about his son Fraser's cystic fibrosis, Mr Brown said he had never wanted his children to appear in the media and suggested the paper's methods should be challenged.
Former News International chief executive Rebekah Brooks has denied the story was obtained through hacking into medical records and said the information came from a source connected to a charity for the condition.
But Mr Brown said: "In 2006 The Sun claimed they had a story from a man in the street who happened to be the father of someone who suffered from cystic fibrosis. I never believed that could be correct."
At the time, only a few medical people knew his son had the condition, he said.
NHS Fife later apologised over the incident as they believed it likely "unauthorised information given by a medical or working member of NHS staff" had enabled The Sun to publish the story, he said.
"If we don't root out this kind of practice I don't think we can say we've dealt with some of the abuses that are problematic for us," he added.
Mr Brown said a Sun journalist had told his press office that the newspaper had a story about his son's condition which it was going to publish.
He said he and his wife had had to deal with the problem of detail of a medical condition being reported when his daughter had died and wanted to "minimise" damage.
Mr Brown said no "parent in the land" would want such detail of a child's illness to be published in a tabloid newspaper.
He added: "There is nothing you can do other than try to limit the damage."
Mr Brown denied "absolutely" that he or his wife had given The Sun "consent" to publish.
He said he had tried - through the Press Complaints Commission - to get editors of major newspapers to agree on limits of coverage about his children.
"We didn't want our children to grow up thinking somehow they were minor celebrities," he said. "We wanted our children to grow up as ordinary young kids."
Mr Brown was asked why his wife had remained friends with Mrs Brooks.
"Sarah is one of the most forgiving people I know," he said. "We had to get on with the job of doing what is expected."
He said his wife and Rupert Murdoch's wife were also involved in the same charity work.
John Wilson, chief executive of NHS Fife, said today in a statement: "Any breach of confidentiality in the NHS is unacceptable. We now accept that it is highly likely that, sometime in 2006, a member of staff in NHS Fife spoke,
without authorisation, about the medical condition of Mr Brown's son, Fraser.
"With the passage of time it has not been possible to identify all the circumstances.
"We believe, however, that there was no inappropriate access to the child's medical records. We are quite clear that conversations about patients are just as much a breach of confidentiality as looking into their medical records.
"In the six years which have passed, NHS Fife has tightened up its procedures on patient confidentiality, and staff have had appropriate training.
"I have apologised to Mr and Mrs Brown and we have taken steps to ensure that what happened to Mr and Mrs Brown and their family should not happen again."
Much of the questioning of Mr Osborne is likely to centre on his role in building relations between the Tory leadership and Rupert Murdoch's News Corp in the periods before and after the 2010 general election.
In opposition, he played a key role in recruiting former News of the World editor Andy Coulson as the Conservatives’ director of communications in 2007.
PA