The moves by trusts come as NHS data revealed last week that hospital flu cases had quadrupled ahead of the new year.

The additional winter pressures saw NHS services in Cornwall declare a critical incident on Friday 3 January.

Kate Shields, chief executive of NHS Cornwall and Isles of Scilly Integrated Care Board said: ‘We are currently seeing a high number of ambulances waiting outside the Royal Cornwall Hospital and of patients in our emergency department. There are also a large number of patients in Cornwall's hospitals who are medically fit to be discharged but are awaiting the right care.'

Meanwhile, relatives in Norfolk and Waveney were urged to postpone visits if they were feeling unwell as hospitals faced a surge in patients with seasonal illnesses.

Rachael Cocker, chief nurse at the Norfolk and Norwich University Hospital, said: ‘This December has been one of the busiest periods we've seen in recent years. Typically, we see this level of flu admissions in mid-late January, but the early spike has added strain on our services.'

Elsewhere, Surrey and Sussex Healthcare NHS Trust said it had stepped down a Critical Incident at East Surrey Hospital.

A spokesperson for Surrey and Sussex Healthcare NHS Trust said: ‘Thanks to the extraordinary measures we have taken and the hard work of our teams over the last 48 hours, we are now able to step down from Critical Incident to Business Continuity – which ensures we can continue to take the necessary steps to support patient care. 
 
‘Our services however remain very busy, and work continues to address the ongoing challenges we are seeing across our East Surrey site from winter viruses and increased demand.'