A private investigator in Cheam has been jailed for six months for unlawfully intercepting messages from Princes Harry and William.
Glenn Mulcaire, 36, immediately issued an apology through his barrister to the royal household for the gross invasion of privacy.
The former AFC Wimbledon footballer had signed a contract with the News of the World worth £104,988 for "research and information".
With Clive Goodman, the royal editor of the newspaper, he systematically hacked into 609 messages left on the mobile phones of senior Clarence House staff.
Goodman, 49, of Putney, was given a four-month jail term as judge Mr Justice Gross called the men's conduct "reprehensible in the extreme".
After the sentencing at the Old Bailey on Friday, Andy Coulson confirmed his resignation as editor of the News of the World.
Mr Justice Gross told the court: "This was serious criminal conduct. It's of very first importance to the fabric of our public life that such intrusive, sustained, criminal conduct should be marked by an immediate loss of liberty".
Mulcaire, a father of five young children, retrieved 122 private messages at his Nine Consultancy firm in the Kimpton Industrial Estate.
He passed on information to Goodman having intercepted messages from Max Clifford, the publicist, Gordon Taylor, chairman of the Professional Footballers' Association, Simon Hughes MP and the model Elle Macpherson.
Suspicion fell on the two men only when royal aides noticed new messages on their phones were registered as old.
It was cynical and ironic, the judge heard, that an advertising brochure for Mulcaire's company offered prominent figures protection from intrusion such as voicemail hacking.
Voicemail hacking - the subject of a Press Complaints Commission inquiry this week - is said to be relatively simple once a person's mobile phone number has been obtained.
Unless the owner has changed the four-digit "default" code, their handset releases messages when the default option is used.
The judge also made a confiscation order for £12,300 on Mulcaire.