Swine flu: 200 fight for life in UK as number of patients in intensive care doubles in a week

Pregnant mother-of-four Fallon Devaney, 25, is in a critical condition in hospital after contracting the disease last week.

Doctors fear that the baby is sapping Ms Devaney's strength - leaving her unable to fight the infection.

It is feared that the swine flu strain may have grown more virulent over the past 12 months with victims quickly becoming dangerously ill.

Intensive care units are warned to look out for the illness in new admissions, with medics urged to use antiviral medicines if they have the least suspicion a patient has it.

Hospital managers have been holding emergency meetings to draw up plans to tackle a further onslaught of cases.

It is thought the cold weather could cause a surge of admissions, putting intensive care units under massive strain.

Analysis by SDI Healthcare, which models flu rates based on reports from GPs and chemists, suggests infection rates are at a five-year high.

It estimates that nine million Britons have been struck down – nearly one in six of the population. Twice the level seen this time last year, the infection rate is 36 per cent above normal, making it the worst flu outbreak in five years.