British prosecutors say they will not press charges over a hoax call by two Australian radio DJs to the hospital where Prince William's pregnant wife Catherine was being treated.

The Crown Prosecution Service said there was no evidence to support a charge of manslaughter, despite the fact that Indian-born Jacintha Saldanha, 46, apparently committed suicide after answering the call.

2DayFM radio hosts Mel Greig and Michael Christian were taken off air "until further notice" by Southern Cross Austereo after Ms Saldanha's death.

The prank call resulted in details of Catherine's recovery from severe morning sickness being revealed on air.

The Crown prosecutors said that while there was some evidence of possible offences under data protection laws "no further investigation is required because any potential prosecution would not be in the public interest".

Malcolm McHaffie, deputy head of Special Crime at the Crown Prosecution Service, said police had handed them a file in December and asked advice about whether a prosecution should be brought.

He added: "It is not possible to extradite individuals from Australia in respect of the potential offences in question."

Jacintha Saldanha apparently took her own life as a result the prank phone call. ( ABC TV )

"However misguided, the telephone call was intended as a harmless prank," he said.

The DJs received death threats over the call, in which they posed as Queen Elizabeth II, Prince William's father Prince Charles, and one of the Queen's corgi dogs.

An inquest heard that Ms Saldanha, a mother of two, was found in staff accommodation at the private King Edward VII's Hospital in central London and there were no suspicious circumstances over her death.

Ms Saldanha left three notes, one of which reportedly criticised colleagues over her treatment at the hospital.

The Australian Media and Communications Commission has opened an investigation into the call.

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AFP