The charges stem from a wider investigation into the British press that was sparked by revelations that journalists at Coulson's former tabloid, the Rupert Murdoch-owned News of the World, had hacked into phones to secure salacious stories.

Coulson was editor of the News of the World from 2003 to 2007 before he took over as Cameron's spokesman from 2007 to 2011, and the latest charges are likely to pose yet more difficult questions for Cameron over his judgment in hiring Coulson in the first place.

Another friend of Cameron's, Murdoch's former British newspaper boss Rebekah Brooks, was also told on Tuesday that she would be also charged with conspiring to make payments to public officials.

"We have concluded, following a careful review of the evidence, that Clive Goodman and Andy Coulson should be charged with two conspiracies," Alison Levitt of the Director of Public Prosecutions said, referring to former royal reporter Goodman.

"The allegations relate to the request and authorization of payments to public officials in exchange for information, including a Palace phone directory known as the 'Green Book' containing contact details for the Royal Family and Members of the Household."

Brooks and Coulson have already been charged in connection with phone-hacking offences - the original crime that sent shockwaves through the British political establishment and exposed the close ties between government and sections of the media.

Brooks, a close friend of Cameron, has also been charged along with her husband and staff over allegations that she sought to interfere with the police investigation.

British police began investigating the conduct of the press last year after it emerged that staff at Murdoch's News of the World had hacked into phones on an industrial scale.

Facing a public backlash, Murdoch closed the mass-selling Sunday title last year and formed an internal committee to cooperate with the police.

Police have since arrested 52 people in connection with making payments to public officials, including staff from Murdoch's daily Sun newspaper, the police and a member of the armed forces.

In addition to Coulson, Brooks and Goodman, prosecutors also charged John Kay, the chief reporter at the Sun from 1990 to 2011 and Bettina Jordan Barber, from the Ministry of Defence.

(Reporting by Kate Holton; editing by Steve Addison)

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