A Norwich woman died after the ambulance crew that may have saved her was initially sent to the wrong address, an inquest has heard.

Holly Johnson died on May 29 last year while she was staying at an address in Trafalgar Street. She was 39.

An inquest into her death was unable to determine whether her death was due to hypoglycaemia or methadone toxicity - or a combination of the two.

However, it heard that crucial moments were lost when an ambulance crew called to her aid was initially sent to the wrong address after her partner Jonathan Bristow gave call handlers an incorrect house number.

Eastern Daily Press: Holly Johnson, who died in Norwich at the age of 39. Picture: Johnson familyHolly Johnson, who died in Norwich at the age of 39. Picture: Johnson family (Image: Johnson family)

The court was told that the pair were staying at the home of a friend of Mr Bristow, rather than at Miss Johnson's home in Lakenfields, when she began to struggle to breathe.

Mr Bristow called for an ambulance at 1.55am and gave an incorrect door number.

When the crew arrived at the address they were told by the occupants they were not required.

Around an hour-and-a-half later, Mr Bristow called back to say Miss Johnson had died.

The inquest heard that the pair had been drinking and using Class A drugs that evening, with police finding drug paraphernalia in the bedroom.

Yvonne Blake, area coroner for Norfolk, said: "There is confusion over the calls he made so I can not answer the question of how he came to give the wrong address."

She added that there had been conflicting evidence given over Miss Johnson's methadone prescriptions, meaning it could not be established whether the amount in her system could have been lethal to her or not.

Giving a narrative conclusion, Mrs Blake added: "Holly was a type-one diabetic and due to uncertainty as to whether she was currently tolerant [to methadone] her death may have been caused either by diabetic hypoglycaemia and/or methadone toxicity."