A soft drink bottle could provide the key to what happened to a young Bradford shop assistant left seriously ill in a poisoning scare.

The 23-year-old woman was left fighting for life in a critical condition after apparently suffering a violent reaction to a drink.

Her condition had improved today. She was out of danger and detectives were hoping to speak to her in hospital.

Police sealed off the Boots store in Darley Street, where the woman works, for five hours on Thursday for forensic examinations to take place.

Officers are continuing to keep an open mind on the cause of the woman’s illness, and are awaiting the results of hospital tests on her, but their inquiries are focusing on a bottle of soft drink that had been left open at her workplace.

A West Yorkshire Police spokesman said: “She had a soft drink bottle with her at work on Wednesday, which had been left open. We will be trying to establish where she got the bottle from.

“The woman has undergone hospital tests. They have been sent away for analysis and we are awaiting the results.”

The spokesman said the woman’s condition had improved and she was now stable.

“We are hoping to be able to speak to her to try to clarify the circumstances and what has happened to her.”

The woman, who has not been named, was taken ill at home on Wednesday night with severe sickness and was rushed to Bradford Royal Infirmary. Hospital staff alerted police.

The police spokesman said: “Inquiries are ongoing and we are still keeping an open mind.

"At this stage all options remain open and the poisoning theory cannot be ruled in or out.”

The police investigation is being led by Det Chief Insp Jim Dunkerley, of the Protective Services Department.

A spokesman for Boots UK said the company was aiding police with the investigation.