More News of the World journalists could become embroiled in the royal phonetapping row which erupted this week when assistant editor (royals) Clive Goodman was arrested, according to sources.
And Press Gazette has been told the practice of 'phone screwing'– illegally hacking into mobile phone voicemail messages – has been widespread throughout Fleet Street.
NoW veteran Goodman, 48, was held at Charing Cross police station on Tuesday and Wednesday in connection with allegations he had breached the Regulation of Investigatory Powers Act. If convicted, he faces a maximum of two years in prison.
Two other men – believed to be investigators used by the News of the World – have also been questioned.
Five Scotland Yard officers raided the News International offices on Tuesday and searched Goodman's desk.
One senior crime journalist said he believed other senior editorial figures are likely to be questioned under caution by the Anti-Terrorist Branch, which is handling the inquiry because of the security implications.
The arrest of Goodman stems from a News of the World diary story which followed a message left by ITN political editor Tom Bradby when arranging an interview with Prince William. He said the inquiry could now widen to include celebrities and politicians.
One well-connected crime reporter said: 'There are a lot more involved. They have been using these methods for some time.
'There could be a paper trail for this. The source would have invoiced the News of the World for this because there would have been too many payments to deal in cash.'He said the police were likely to seek a warrant to search the NoW's paper records in Peterborough.
He added: 'When you've got a contact that can do this, everyone will use them – the newsdesk will use them, showbiz will use them. There will be a lot more to come out than just this specific case.'
Several Fleet Street sources have told Press Gazette about the prevalence of phone screwing – which is not only against the law, but clearly breaches the Editors' Code of Practice.
One former red-top news reporter explained to Press Gazette how voice message hacking works. He said: 'It is extremely prevalent among the Sunday tabloids – it goes on all the time.
'The process is known as screwing a phone. Most people who have mobile phones don't change the factory setting on their voicemail – it could be four zeros or 1234, something very simple like that. You might try using their birthday or something like that if they have changed the setting.
'It is a far more common practice than members of the public realise. There are some journalists who quite revel in their ability to do this.'
A former tabloid investigative journalist, who asked not to be named, said: 'Loads of people were doing it. All the networks have tightened up on their security, so I'm really surprised if it's still going on.'
He added: 'What Fleet Street lovingly terms the dark arts have very much been on the decline, certainly for the last year-and-a-half to two years, because the technology has caught up and it's harder to do it.
"Any remote access phone service can be screwed. It was a little loophole that most of the networks have shut down.
"The Information Commissioner's report that came out four of five months ago gave every detail, cough and spit of what journalists had been up to. Then every single private investigator in town said, 'No more. We're not doing this for journalists.'
"A lot of places would offset their darkest arts work to a private eye so that there was no paper trail. They were protecting themselves from a staff reporter getting nicked."
One 'quality' journalist told Press Gazette that phone "screwing" is not confined to the tabloids. He said: "It's still pretty unusual, but I can think of one or two quality newspaper journalists who will know people or had some involvement in the past. Sundays are particularly prone because they've got to come up with scoops all the time and that's where the pressure is, so you can think of some of the more sensational so-called quality Sundays doing it."
On the ethics of "screwing", he said: "There might be some circumstances if there was a terrorist incident or you were sure that a person was involved in some amazing criminality, but most of the time it just makes the industry look crap."
An ex-News of the World staffer said the practice was so prevalent on the paper when they were there that journalists even did it to each other: "When I was on the paper there was a war between the features department and news. Features would hack into the phone of somebody who was on the newsdesk to see what story they might be working on."