As the Metropolitan Police launch a "robust" new investigation into phone hacking amid "significant new information", we unpick the long-running case which refuses to go away.
25 February 2011 
Sienna Miller's legal action is thought to have precipitated action by the CPS As the Metropolitan Police launch a "robust" new investigation into phone hacking amid "significant new information", we unpick the long-running case which refuses to go away.
What is the row about?
The increasingly complex fallout of a 2006 court case which saw the News of the World's (NoW) royal editor and a private investigator jailed for hacking into the mobile phones of royal aides. A series of inquiries and legal cases is exploring just how widespread the practice was, with implications for the police, celebrities and politicians.
How did the NoW phone-hacking case first emerge?
The paper published a story about a knee injury to Prince William. The royal began to fear his aides' mobile phone voicemail messages were being intercepted. Complaints by three royal staff sparked a police inquiry.
What was the outcome?
In January 2007, royal editor Clive Goodman and private investigator Glenn Mulcaire were jailed for four months and six months respectively.
What's the relevance now?
As claims that phone hacking was widespread rumble on, more and more celebrities and public figures are launching civil legal actions against both the paper and the police.
The Mulcaire/Goodman case first revealed several public figures had been hacked. Two of them - Gordon Taylor and Max Clifford - brought private cases against the NoW and received reported settlements of £700,000 and £1m respectively. The cases were settled before key documents were revealed in court.
Why does all this matter?
It is against the law to intercept voicemail messages on mobile phones. If NoW executives acted illegally by ordering Mulcaire to hack the phones then they could face charges. The ongoing allegations also have the potential to damage the police, politicians and Rupert Murdoch's business interests.
How?
The Met has been accused of failing to inform many of Mulcaire's alleged victims when they recovered files from his home which referred to a long list of public figures. Four people are seeking a judicial review into the police handling of the case and the Met has launched a "robust" inquiry led by a specialist team.
PM David Cameron's judgement has been questioned after he appointed ex-NoW editor Andy Coulson as his director of communications. Mr Coulson resigned his post saying the media storm surrounding ongoing hacking claims had distracted him from doing his job properly. He denies any knowledge of hacking during his editorship.
The scandal also threatens News International, which owns the NoW. The drip-drip of new claims comes at a bad time for the group, which is lobbying to secure ownership of the 61% of satellite broadcaster BSkyB it does not already own. Mr Murdoch is reported to be enforcing a "zero-tolerance" attitude to those found guilty of hacking.
Who do we know was hacked?
Aside from members of the Royal Family's staff, the Goodman case revealed publicist Max Clifford, Professional Footballers' Association chief executive Gordon Taylor, Lib Dem MP Simon Hughes, model Elle Macpherson and sports agent Sky Andrew had all been victims.
Who else is claiming they were victims?
Lawyers for actress Sienna Miller, actor and comedian Steve Coogan, and former Sky Sports presenter Andy Gray are suing the NoW for breach of privacy after the Met confirmed their clients' personal details were in the possession of Mulcaire following a raid on his house. In February 2011, a judge said Mulcaire would have to provide evidence in the cases brought by Mr Coogan and Mr Gray.
