An exploding vape battery caused a fire that led to 40 people being evacuated from a hospital.

Part of a outpatient day ward at the Royal Free Hospital in Hampstead was damaged when the blaze broke out in a backpack on Tuesday.

The London Fire Brigade was called to the hospital, in Pond Street, at 12.24pm.

Hospital staff evacuated around 40 people before crews arrived.

A fire brigade spokesman said the blaze was safely extinguished using an extinguisher by a member of hospital staff before firefighters arrived.

Two men and four women were assessed for smoke inhalation.

The fire brigade said the incident was over for crews by 1.26pm.

The cause is believed to have been accidental, and probably caused by the failure of a lithium battery in a rechargeable vape.

A spokesperson for the Royal Free London said: “We would like to thank the nursing team for their phenomenally quick response, which ensured no-one was hurt.

"Staff made sure patients were safely evacuated and patient care has continued to be delivered in a safe and timely way. Thank you to the London Fire Brigade for attending.”

A five-seat bay damaged by the fire was closed but is due to reopen this afternoon (Thursday).

Patients are not allowed to smoke or vape in the hospital.

Firefighters from Walthamstow, Stoke Newington, Holloway and surrounding fire stations attended the scene.