Emergency bells in the cells of Wandsworth prison are frequently being abused by inmates - making it hard for officers to answer them on time, an inquest has heard.

Robert Parchment, 48, had a heart attack last November and was taken by ambulance to St George's Hospital, where he was pronounced dead, Westminster Coroner's Court heard.

Although coroner Dr Shirley Radcliffe described Mr Parchment's condition as a "timebomb" and said an earlier response would have made no difference, it took staff at least 10 minutes to reach him after his cellmate pressed the bell.

Prison officers told the court that the vast majority of inmates press the bells for minor reasons, such as to ask what the time is.

Alan Waterman said: "A lot of them are trivial. I've had them asking for salt for their dinner or saying their potatoes are not cooked. They are just attention-seeking bells but their real purpose is for an emergency."

HMP Wandsworth governor Ian Mulholland, who is responsible for 1,644 prisoners and 750 staff, estimated that up to 95 per cent of calls from cell bells are for non-emergencies.

"If prison officers do nothing all day but answer cell bells they would get nothing done," he said.

In response to recommendations from the Prisons and Probation ombudsman, Mr Mulholland has asked his staff to answer all calls within five minutes, the court heard.

And to deter prisoners from pressing the bell unnecessarily, they are moved down the privilege order if they frequently abuse the system.

Dr Radcliffe said: "The cell bell is a peripheral issue in Mr Parchement's case but not in the whole scheme of things. We don't want to be in a situation where it's someone who's cut their wrist and the cell bell's not answered."

Jamaican-born Mr Parchment, who had a history of substance abuse, committed a number of offences such as theft.

He had recently begun a 19-month sentence in Wands- worth, and was on a detoxification programme, when he collapsed in his cell shortly after officers started their morning shift on November 4. His cellmate pressed the bell and started banging on the door, alerting officers.

Nurses from the detoxification unit checked Mr Parchment's vital signs, and staff radioed for a GP, switching their request to an ambulance when there was difficulty in contacting a doctor.

Mr Parchment was pronounced dead in hospital.

Although he had never complained of chest pains in the past, the court heard that sudden death is sometimes the first sign of heart disease.

The jury returned a verdict of natural causes.