WALES' ambulance service has apologised to the family of a Gwent woman who died of an overdose, for an "unacceptable delay" in responding to 999 calls.

An inquest concluded this week that a delay in sending an ambulance to 41-year-old Karen Watkins is unlikely to have affected her chances of survival, given the significant amount of the drug venlafaxine, prescribed to treat depression, subsequently found in her system.

But Welsh Ambulance Services NHS Trust medical director Brendan Lloyd said: "We think it was an unacceptable delay and for that, we’re very sorry."

On February 17 last year, around 90 minutes after the first of three 999 calls, and with her condition deteriorating, Mrs Watkins was taken to the Royal Gwent Hospital in the back of a police car, from her home at the Unicorn pub in Cwmynyscoy, Pontypool. She died later that day.

“Following Mrs Watkins’ death, the trust launched a full investigation to understand exactly what happened, and to establish what lessons could be learned," said Mr Lloyd.

“We discovered that the third 999 call made for Mrs Watkins was incorrectly categorised as a ‘Green’ call when it should have been a high priority ‘Red’ call.

"The staff in question have since been given an opportunity to reflect and learn from this sad incident."

Senior coroner for Gwent David Bowen recorded a verdict of suicide.

Mrs Watkins' mother Jean Thomas insisted at the hearing that her husband inquired about an ambulance some time after her daughter's friend Geraldine Jones made the first 999 call, and had been told one was on its way.

February 17, 2014, was extremely busy for the ambulance service, with high demand, calls stacking up, and ambulances delayed at hospitals.

The inquest was told the normal response should be that help is being arranged, rather than that an ambulance is on its way.

Mrs Thomas was adamant that with a speedier response, her daughter may have had a chance of survival.

Mr Lloyd said new ways of assessing 999 calls have been introduced, to ensure patients receive the correct response first time around.

“We have been in close and regular contact with Mrs Watkins’ family throughout this process, and will remain so in order to address any outstanding questions or concerns they may have," he said.

“In the meantime, once again, we would extend our sincere condolences to Mrs Watkins’ family.”