The Queen Elizabeth II Hospital in Welwyn Garden City, Hertfordshire, issued the appeal for nurses to cut short their holidays after being hit by its own "mini" flu epidemic at the same time as it was having to cope with an above average level of other admissions.
Latest figures suggest that 128 out of every 100,000 people in the United Kingdom have gone down with the virus - double the rate at the start of the month.
With most of the country returning to work today, three strains of flu - Wuhan, Singapore and Beijing A - are known to be circulating in Britain. The highest numbers of cases have been reported in the North and in the 15-to-24 age group.
The Department of Health said the present number of cases was below epidemic level. In a bad year - such as 1989, when 25,000 Britons died of flu - infection rates can exceed 400 out of every 100,000.
Ruth Ashmore, of the Queen Elizabeth II Hospital, said: "We issued an appeal over local radio for nurses on time off to come in and help out.
"It is not a nice thing to do, because nurses ... deserve their holidays, but it is proving difficult because of staff sickness and sheer patient numbers. We have had to open some surgical beds to general patients because there are so many of them."
The flu scare came as icy weather sent temperatures plunging to -7C in parts of Britain; even the river Thames froze over in places. The Royal Society for the Prevention of Accidents warned that appearances could be deceptive, and that no one should assume ice was thick enough to stand their weight.
According to the London Weather Centre, today will bring more "bitterly cold" conditions.Reuse content