Paramedics should ensure there is adequate ventilation within ambulances during waits to hand over patients to A&E, Public Health England has said.

Guidance issued by the agency said patients should only wait in ambulances in “exceptional circumstances”.

More than 3,000 patients waited more than an hour to be handed over from ambulance teams to A&E staff at hospitals in England, the latest figures show.

In the event of a delay, ambulance staff have been told to try and rotate clinicians regularly to prevent prolonged exposure time to patients and to allow staff to change personal protective equipment (PPE) and have a drink.

Vehicles may need to remain running to allow ventilation systems to dilute the level of virus particles and maintain air circulation within the patient compartment.

Patients, and those with them, should wear surgical face masks provided this does not interfere with treatment, such as when receiving oxygen therapy.

Surfaces should be decontaminated more frequently and during the delay if possible.

However, the guidance said there was no need to automatically increase the level of PPE worn by ambulance staff unless the level of care indicates it is required.

A total of 3,333 ambulance delays of more than 60 minutes were recorded across all acute trusts in the seven days to January 17 — down from 5,513 in the seven preceding days, up to January 10.

However, a handover delay does not always mean a patient has waited in an ambulance.

They may have been moved into an A&E department, but staff were not able to complete the handover.