NO charges will be brought over a prank call to a hospital about the Duchess of Cambridge, which was taken by a nurse who later took her own life, the Crown Prosecution Service said.

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) has 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."

Mr McHaffie 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... no further investigation is required because any potential prosecution would not be in the public interest," he said.