Flu rates continued to increase in much of the UK in the week before Christmas – as hospitals braced themselves for post-holiday pressures, according to the latest figures.

Limited information from GP practices suggested a further increase in the number of patients with flu-like illness while pressure on hospitals from flu was at “moderate intensity,” Public Health England reported.

A number of hospitals reported waits for four hours or more to see a doctor in emergency departments earlier this week. Derriford Hospital, Plymouth, issued a regional alert, warning of waits of up to ten hours – but overnight succeeded in reducing times to 4.5 hours. The nearby Royal Devon and Exeter Hospital reported similar waiting times for 19 patients waiting to be seen.

The PHE analysis found an 11% increase in flu hospitalisation rates in the week before Christmas. 22 care homes had confirmed flu outbreaks as did 15 hospitals, an increase of nine in a week.

However GPs in Northern Ireland reported a reduction in patients with flu-like illnesses. The region had reported the highest rates in the UK. Public Health England said rates of viral infection might have peaked in the north of England but continued to increase in the south -based on reports from NHS 111 and its own GP surveillance system.