As critical incidents are declared in at least a dozen hospitals, we look at testing and protection advice

Over the past week, at least a dozen hospitals have declared critical incidents as the rise in flu admissions and respiratory illnesses has led to “exceptionally high demands”.

Hospitals in Birmingham, Cornwall, Hampshire, Liverpool, Northamptonshire and Plymouth have been among those affected, with figures showing the number of people admitted to hospital in England with flu quadrupled last month.