The nurse who put through a prank call from radio DJs to Duchess of Cambridge’s private hospital ward has been found dead in Marylebone. She has been named as Jacintha Saldanha, 46.

Ms Saldanha was found collapsed and unconscious at an address near the King Edward VII Hospital Sister Agnes in Beaumont Street, Marylebone, shortly before 9.30am today. Paramedics pronounced her dead at the scene in nearby Weymouth Street.

Jacintha is said to have been the nurse manning the hospital’s switchboard when Australian radio DJs Mel Greig and Michael Christian impersonated the Queen and the Prince of Wales, fooling her into putting them through to the ward where they were given a condition update on Kate, who was being treated for severe morning sickness at the hospital.

Police are treating the death as unexplained at this early stage, and her next of kin have been informed.

The Duke and Duchess of Cambridge this afternoon said they were “deeply saddened” by the death.

The statement from St James’s Palace added: “Their Royal Highnesses were looked after so wonderfully well at all times by everybody at King Edward VII Hospital, and their thoughts and prayers are with Jacintha Saldanha’s family, friends and colleagues at this very sad time.”

The Palace later stressed: “At no point did the Palace complain to the hospital about the incident. On the contrary, we offered our full and heartfelt support to the nurses involved and hospital staff at all times.”

The hospital said in a statement: “We can confirm the tragic death of a member of our nursing staff, Jacintha Saldanha.

“Jacintha has worked at the King Edward VII Hospital for more than four years. She was an excellent nurse and a well-respected and popular member of staff with all her colleagues.

“We can confirm that Jacintha was recently the victim of a hoax call to the hospital. The hospital has been supporting her at this difficult time.”

Hospital chief executive John Lofthouse said: “Our thoughts and deepest sympathies at this time are with her family and friends. Everyone is shocked by the loss of a much-loved and valued colleague.”

Lord Glenarthur, the hospital’s chairman, said: “This is a tragic event. Jacintha was a first-class nurse who cared diligently for hundreds of patients during her time with us. She will be greatly missed.”

The Australian radio presenters, from 2Day FM, remarked during their show how their efforts were the “easiest prank call ever made”. The station was expected to issue a statement about the death later today.

The DJs made their call at around 5.30am on Tuesday and are thought to have been put through to Ms Saldanha. The prank call was deeply embarrassing for the hospital, which is the medical institution of choice for the royals.

Mr Lofthouse said on Tuesday: “I’ve received advice that what the Australian broadcasters did may well have broken the law. On the other hand they’ve apologised for it so we’re going to have a long and careful think about what, if anything, we do.”

The prank call was pre-recorded and vetted by lawyers before being broadcast to listeners in Sydney.

In their initial apology the two presenters said: “We were very surprised that our call was put through. We thought we’d be hung up on as soon as they heard our terrible accents.

“We’re very sorry if we’ve caused any issues and we’re glad to hear that Kate is doing well.”

Dr Peter Carter, chief executive and general secretary of the Royal College of Nursing, said: “This is tragic news, and the thoughts of all at the Royal College of Nursing go to the family of Jacintha Saldanha.

“It is deeply saddening that a simple human error due to a cruel hoax could lead to the death of a dedicated and caring member of the nursing profession.”