Stuart Hoare (pictured arriving at Hatfield Coroners Court in November) told the inquiry of the 'strange world' described by his late brotherCredit: Chris Radburn/PA
Appearing at the inquiry today, Stuart Hoare said he was keen that his late brother's voice should "still be heard", following his death in July, which a postmortem concluded was not suspicious.
Sean Hoare was one of the first journalists to make on the record allegations of phone hacking at the News of the World, in an interview with the New York Times last year.
However, director of public prosecutions Kier Starmer said in December that Hoare had refused to comment when interviewed by police on the matter.
Hoare did speak out again this year in an interview with BBC Panorama in March, when he claimed phone hacking was "endemic".
Today in evidence to the inquiry, based on his witness statement published online, Stuart Hoare said that - based on what his brother had told him - he wanted to "make it very clear that this alleged practice not only went on at the News of the World but also went on at the Sun".
"It was a practice taken to the News of the World", Stuart Hoare said. "It was a routine at the Sun. It was probably more daily at the News of the World."
Stuart Hoare added that he was told hacking was "used widely" at both papers.
"To listen to Sean's stories of what went on, it didn't even seem like work to me. It seemed no one was in control ... as long as they delivered an article. Early on in the week all the better. It was a very strange world they operated in."
Stuart also told the inquiry he would be happy to pass on copies of emails sent from his brother after he had finished working at the News of the World and the Sun.
"I was fortunate enough to retain certain information Sean had left with me. The emails in their entirety are handed over to the police and I believe they will be acting on those emails at some given time."
The inquiry also heard from Stuart Hoare that his brother had been "struggling" in his last two years at the News of the World.
"There was an enormous amount of pressure put on him and other reporters to produce articles that would sell," he said.
"He certainly wasn't enjoying it. He was bringing his work home, he was drinking more, trying to run away from certain issues going on at the paper and it wasn't a nice part of his life, he was certainly struggling."
But despite this he said when Hoare was "asked to leave", it caused him to feel as though "his world had fallen apart".
"He really felt lost. I can't tell you how much Sean enjoyed journalism."
Stuart Hoare was questioned on whether he believes his brother was telling the truth.
"I think sitting here today demonstrates that everything Sean said, every statement Sean made was the truth," he said. "I sit here with a lot of pride."
Responding to whether or not he believes his brother's account could have been exaggerated, Stuart Hoare said: "No, I don't think he would have exaggerated, he was very serious."
Stuart Hoare added that he is "disgusted by what went on".
"It upsets me the amount of pressure these journalists at the News of the World were put [under] and to see the demise of my brother through this was shocking."
News International had not responded to a request for comment at the time of writing.