The Royal Preston Hospital has been put on standby to deal with a potential fresh terrorist attack.
The site, which is a major trauma centre for Lancashire and South Cumbria, is one of 27 across the country warned by NHS England to “prepare for a further incident” - possibly over the Bank Holiday weekend.
The message sent to the trauma units came from Chris Moran, NHS England’s national clinical director for trauma.
The message states: “The trauma community in Manchester has provided a tremendous response to the atrocity on Monday night and this is a credit to their dedication and clinical skills, and also the preparation that has taken place.
“You will be aware that we have a bank holiday weekend approaching.
“There are a number of things that all trauma units and major trauma centres can do to prepare for a further incident and I should be grateful if you could disseminate these within your network so that frontline clinicians are aware.”
The letter was obtained and published by The Health Service Journal.
A spokesman for Lancashire Teaching Hospitals NHS Foundation Trust, which runs the Royal Preston Hospital, said: “NHS England has written to all NHS providers following the Prime Minister’s announcement that the country’s security alert level has been raised to critical.
“This sets out a range of precautionary measures, in line with longstanding planning protocols, that we are required to have in place at this time.
“We have longstanding and robust plans in place to prepare for a major incident.”
A spokesman for NHS England said: “Since the [Joint Terrorism Analysis Centre] has announced the threat level has changed from severe to critical, this triggers longstanding, tried and tested NHS protocols reflected in this letter, which reminds NHS organisations of the precautionary measures they need to take ensure care is in place should it be needed.”