The parents of a baby girl who died while waiting for a delayed heart operation told an inquest they had been let down by the NHS “in the worst way possible”.

Six-month-old Iris Day, who was born with a heart defect and Down’s Syndrome, died after her operation was scheduled and cancelled three times.

Her mother Hannah Day, 29, told an inquest in Chelmsford she and husband Ben, 41, were not at their daughter’s bedside at Colchester Hospital when she died as they were given “false reassurance” about her condition and had gone home to fetch belongings.

Essex’s assistant coroner Jolanta McKenzie, recording a narrative conclusion after a two-day hearing, said Iris had been listed for surgery at the Evelina London Children’s Hospital, but this was not undertaken and she was admitted to Colchester Hospital while in “respiratory distress”.

Iris’s condition was not identified by treating clinicians, her condition worsened and she died.

“There were failings in the care provided by Colchester Hospital,” said Dr McKenzie.

Iris, whose family live in Great Braxted, Essex, died on December 2, 2016, after she suffered respiratory problems.

Mrs Day said that at Colchester Hospital they were given “really quite false reassurance that Iris was stable” which had led them to go home to collect some belongings for Iris.

She said they later received a call from the hospital informing them that Iris had deteriorated, and when they got back to the hospital they found her lifeless.

“From a human point of view, the impression we’ve got is we haven’t felt there’s been a whole lot of compassion from staff,” Mrs Day said.

“Iris, to them, might have been another patient but she was absolutely our whole world.”

Insurance broker Mr Day said: “I genuinely feel the majority of NHS staff who came into contact with Iris in her short life let her and her family down in the worst possible way.”

Dr Kalyaan Devarajan, a paediatric consultant at Colchester Hospital, said an investigation identified “a series of deficiencies in certain aspects of care resulting in (Iris’s) sad demise” at Colchester Hospital.

These include a failure to contact the Evelina Hospital, and a failure to recognise that Iris’s increasing heart rate was a significant deterioration.