Joan Smith: My phone may have been hacked. So why wasn't I told?

The message came out of the blue: a detective from Operation Weeting was trying to get hold of me. Operation Weeting? That's the name of the new inquiry set up by the Metropolitan Police into the long-running phone-hacking scandal. My stomach lurched and I realised straightaway that it could mean only one thing. I now know that my name, address, home and mobile phone numbers appear in handwritten notes seized by the police in 2006 from a private detective, Glenn Mulcaire, who worked for the News of the World.

Yes, I did say 2006. Detectives have had Mulcaire's notes containing thousands of names and phone numbers for five years, yet most of us are only now discovering that we are "potential victims" (in the Met's carefully chosen phrase) of phone hacking. It's a jaw-dropping revelation, even though details of my private life have occasionally surfaced in the tabloids. If I was of interest to Mulcaire, presumably because of my then relationship with a Labour MP, how wide is this scandal going to spread? The questions are endless, but the most pressing is why it's taken the police so long to warn up to 4,000 of us that our voicemails may have been listened to illegally.

A handful of people were told, but until two days ago the Met was still insisting that the figure should be kept secret. Now we've discovered that the initial investigation five years ago led to precisely 28 people being warned; in July 2009, another eight were told that the security of their mobiles might have been compromised. That's 36 in all, prompting one of yesterday's pithier headlines: "3,964 to go?"

It was only on Tuesday of this week that the Met's acting deputy commissioner, John Yates, admitted in a letter to the Conservative MP John Whittingdale, chair of the Culture, Media and Sport SelectCommittee, that less than 1 per cent of us were contacted during the original investigation. "I have accepted that more could and should have been done in relation to those who may have been potential victims," he said, with breathtaking understatement.

Phone hacking is a criminal offence. In August 2006, the News of the World's royal editor, Clive Goodman, was arrested on suspicion of hacking the mobiles of members of the royal household and accessing voicemail messages. In January 2007 he pleaded guilty to phone interception charges and went to prison for four months; at the same time Mulcaire, who was on a retainer from the paper, was imprisoned for six months.

On the day the two men were sentenced, the resignation of the paper's then editor, Andy Coulson, was announced; Coulson has always denied all knowledge of phone hacking and later became David Cameron's communications director. He resigned the post in January this year when it became clear that media coverage of the phone-hacking scandal was not going to go away.

Earlier this month, officers from Operation Weeting arrested the News of the World's chief reporter and former assistant editor on suspicion of conspiring to intercept mobile phone messages; both have been released on bail. Also this month, the paper's parent company, News International, publicly apologised to eight victims of phone hacking including the former culture secretary Tessa Jowell and the actor Sienna Miller.

It is chiefly thanks to Miller's persistence in returning to the courts that the extent of the practice has finally begun to emerge, and she's been offered £100,000 to settle her lawsuit. Four people, including Miller, have been told that their cases will take precedence in court proceedings; the other three are Miller's stepmother, Kelly Hoppen, the football agent Sky Andrew and the football commentator Andy Gray.

Even before this week's revelation that so few people received warnings from the police that the security of their mobiles might have been compromised, politicians had begun to sound the alarm and demand a public inquiry. "There are some very big questions," Whittingdale told the BBC a couple of weeks ago. "What I find [most] worrying is the apparent unwillingness of the police, who had the evidence and chose to do nothing with it."

The MP believes that the scandal may even have compromised government security, suggesting that it was "pretty extraordinary" that newspapers were apparently able to listen in to "the private conversations of Downing Street, royal staff and others".

His call for an inquiry was echoed last week by the Labour leader, Ed Miliband, who wants to see an independent review of newspaper regulation and practice. Miliband's statement was regarded as a high-risk move for a leader whose party is out of power and needs friends in the media. But I suspect that he's ahead of the game and has grasped the fact that the repercussions of this scandal – and its potential to damage the reputation of the British press – are likely to be wider than most people have yet realised. One possible victim is the Press Complaints Commission, the industry watchdog whose response to allegations of widespread phone hacking has been tardy and far from rigorous.

I write crime novels, but I never imagined a plot as seedy as this one. The idea that I was targeted by a private investigator who obtained my home address and phone numbers, and perhaps those of my friends – there are several so far unidentified numbers next to my name in Mulcaire's notes – makes me feel sick and angry. The realisation that the police could have warned me to take steps to protect my mobile five years ago, and sat on the information all this time, is beyond belief.

I don't yet know for certain whether my phone was hacked. I have a meeting with the police next month and I've had to contact O2, the mobile operator I was using at the time, with a series of technical questions. I assume that thousands of other people – peers, MPs, actors, sports stars, maybe other journalists – are going through the same process. Where will it all end? I passionately believe that a free press is a cornerstone of democracy, and I hate to see it at risk because of this sick obsession with celebrity.

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