Twelve years ago, Welsh salesman Steven Nott pulled over at a motorway services in something of a panic.
He had been without a mobile phone signal for hours because the network was down, and he could not access the voicemail messages that were essential for him to do his job.
So he rang his supplier, Vodafone, on a landline at the services, and was astonished to be told he could access all his voicemails simply by tapping in a default pin number. And so, for that matter, could anyone else.
He says he was "gobsmacked", and shortly after the incident, in 1999, complained not only to Vodafone but took his story to his local newspaper, and to the police.
The South Wales Argus ran the story under the headline "Sales boss reveals security problem".
In words eerily prescient of the phone-hacking scandal, which was to erupt years later, he told the paper: "Vodafone has millions of users, and many of them will be MPs and high-ranking government officials, people with highly sensitive information at their fingertips.
"Unauthorised accessing of someone's message service is on a par with tampering with their mail."
But Vodafone was slow to act. The company did not address the issue for some years. In the meantime, Mr Nott was, by his own admission, becoming obsessed by what he had discovered.
He telephoned the Daily Mirror, hoping to give them a scoop that they would splash across their pages, alerting other phone users to the vulnerability of their mobiles to hacking.
He says that over a period of several days he spoke to somebody on the paper's newsdesk, who was excited by the story.
Mr Nott claims the Mirror said they were planning to run a piece about how celebrities' phones could be hacked.
He says they told him they had "everybody on to it" as they had a massive bank of phone numbers and were ringing everyone to see how they would react to news their mobiles could be tampered with.
But the Mirror never published the story. Mr Nott says the newspaper did, however, pay him £100.
The owner of the Mirror, Trinity Mirror, said on Saturday: "We are not going to dignify this with a comment."
Next, Mr Nott took his story to the offices of the Sun in Wapping, where he met Paul Crosbie, who was then the newspaper's consumer affairs correspondent.
Mr Crosbie now works in PR, but he confirmed to the BBC Mr Nott's account of his visit.
"I did meet Steven, was surprised by what he'd discovered. I'd never heard of it before he came to the office," he said.
"I wrote up what I thought was a very good story, but it never ran. There was only room for a certain number of stories in the Sun, so a lot did get spiked for whatever reason."
By this time Mr Nott said he was regretting his actions.
"It didn't take me long to realise what I had done. I couldn't believe I was so stupid to tell a national newspaper how to get hot news for free just by hacking into someone's phone," he said.
"I was on a campaign to raise public awareness and it was backfiring."
Mr Crosbie said: "I don't know whether the information he gave me led to today's events. I only know that I wasn't asked to demonstrate the flaws to anyone."
News International, the publisher of the Sun, declined to comment.
Steven Nott does not claim to be the first person to discover how easy it was to hack a person's mobile phone.
But he does believe he was the first to try to bring it to the attention of the wider public by telling journalists about it. He says he did not anticipate that journalists would use the technique themselves.
"I'm appalled because I really do seriously think I may have inadvertently started this in the early days," he said.
Last month detectives from Operation Weeting, who are investigating the phone-hacking scandal at the News of the World, travelled to Wales to interview Mr Nott.