Queen’s Hospital in Romford “experienced an issue with oxygen pressure” last month and had to transfer patients to King George Hospital in Goodmayes.

Barking, Havering and Redbridge University Hospitals NHS Trust (BHRUT), which manages the two hospitals, transferred 25 patients from one hospital to the other.

Chief operating officer Shelagh Smith confirmed: “On Wednesday April 1, we experienced an issue with oxygen pressure at Queen’s Hospital.

“To keep our patients safe, and as we had significant bed capacity at King George Hospital, the London Ambulance Service were asked to take patients directly to King George Hospital.

“In addition, 25 patients who had been assessed at Queen’s Hospital were safely transferred to King George Hospital.

“By that evening our oxygen pressure was back to normal and has remained so.”.

Health campaigner Andy Walker has asked why the incident was not publicised at the time and insists more information is needed on why it took place and how it can be prevented in future.

He said: “To my mind that was a substantial incident. It’s a cause for concern and we need more information.

“It’s important that the public know what went on and if the issue has been fixed.”

On March 30, NHS England wrote a letter to hospital bosses after a London teaching hospital ran out of oxygen for coronavirus patients, warning them to take urgent action.

BHRUT has not confirmed the cause of the oxygen pressure issue.