No charges will be brought against Australian DJs Mel Greig and Michael Christian over hoax calls to the hospital treating the Duchess of Cambridge, the Crown Prosecution Service said today.

Australian DJs Mel Greig and Michael Christian made the hoax call to the King Edward VII's hospital in central London, posing as the Queen and Prince of Wales when Kate was being treated for a rare form of pregnancy sickness.

Nurse Jacintha Saldanha, who transferred them to a colleague, who then described Kate's condition in detail, was found hanged a few days after the incident, sparking a backlash against the 2Day FM DJs.

The Crown Prosecution Service (CPS) today announced that no charges will be brought over the hoax calls.

Malcolm McHaffie, deputy head of special crime at the CPS, said there was no evidence to support a manslaughter charge and any potential prosecution would not be in the public interest.

He said: "As is well known, on December 4 2012 Mel Greig and Michael Christian, both radio presenters in Australia, made a telephone call to the King Edward VII's Hospital in London, where the Duchess of Cambridge was receiving treatment, in which they pretended to be members of the Royal Family.

"During the course of the call, private information about the Duchess's health was given, in good faith, to Ms Greig and Mr Christian and the call was later played on a radio station in Australia.

"Subsequently, Jacintha Saldanha, a nurse at the hospital who had initially taken the call but who had not herself passed on the information, tragically took her own life."

He said Scotland Yard provided the CPS with a file of evidence on December 19 and asked advice on whether a prosecution should be brought.

"Having carefully reviewed the evidence currently available, we have concluded that there is no evidence to support a charge of manslaughter and that, although there is some evidence to warrant further investigation of offences under the Data Protection Act 1998, the Malicious Communications Act 1988 and the Communications Act 2003, no further investigation is required because any potential prosecution would not be in the public interest," he said.

McHaffie said the CPS had taken into account, among other matters, that it is not possible to extradite people from Australia on the potential offences in question.

He also said it considered that "however misguided, the telephone call was intended as a harmless prank".

"The consequences in this case were very sad. We send our sincere condolences to Jacintha Saldanha's family."