By Torin Douglas
BBC media correspondent
The voicemail of mobile phones can be a vulnerable target
When the News of the World's royal editor Clive Goodman was jailed, along with a private investigator, the newspaper industry was united in condemnation.
Goodman had pleaded guilty to hacking into the mobile phones of royal staff.
The paper's editor, Andy Coulson, resigned, saying he took full responsibility for what happened on his watch - but without his knowledge.
His successor, Colin Myler, said: "It was an exceptional and unhappy event... involving one journalist."
The industry watchdog, the Press Complaints Commission, said the actions of the jailed men were deplorable.
It launched an inquiry into the use of subterfuge by journalists, which resulted in stricter new rules.
But the publicist Max Clifford, whose phone messages had also been hacked into, said the practice was becoming far more widespread in tabloid journalism.
He also acknowledged that very occasionally it could be seen as legitimate.
"The only way you can justify this kind of activity is when the end product is something which genuinely the nation can benefit from - but for tittle tattle and gossip the end does not justify the means."
That was two and half years ago.
Max Clifford says phone hacking is spreading among the tabloid press
Now - following an out of court settlement between the publishers of the News of the World and Gordon Taylor, the chief executive of the Professional Footballers Association - the Guardian claims to have uncovered evidence that such underhand methods are far more widespread at the News of the World than was acknowledged.
And it is not just referring to the tapping of mobile phones.
It cites evidence from the Information Commission - which polices the Data Protection Act - that private investigators have also been widely used by the News of the World and other national newspapers to extract other confidential data, from police records, the DVLA, the Inland Revenue, phone companies and banks.
It is known as "blagging" - pretending to be someone you are not in order to gain the information you are not entitled to.
The Information Commission has now confirmed that, following a court order last year, it passed on information to lawyers for Gordon Taylor, showing that 27 journalists working for The News of the World and four for The Sun had acquired people's personal information through blagging.
It is not the first time the Commission has exposed the issue.
Three years ago, in a report called What Price Privacy? it revealed it had uncovered records of information being supplied to 305 named journalists working for a range of newspapers.
It says such activity is "certainly or very probably illegal", subject to a defence that the resulting story was "in the public interest".
The general secretary of the National Union of Journalists, Jeremy Dear, said at the time: "We never condone obtaining information by criminal means or by impersonation except where there is an overwhelming public interest.
"However, it must be understood that there are times when a journalist must use exceptional means to investigate exceptionally important matters where all other methods have been exhausted, and he or she should not be punished for this if the public interest is clearly being served."
No-one is claiming there was a public interest in most of what the News of the World is alleged by the Guardian to have been doing.
And now there will be renewed scrutiny by the police, MPs and regulators of the ethics and legality of what has been done in the name of tabloid journalism.