The worker is not exhibiting symptoms of the disease and the incident is not related to that of five military healthcare workers brought back in recent days, Public Health England (PHE) said.
A female military healthcare worker who tested positive for the deadly virus is currently being treated in a high-level isolation unit at the Royal Free Hospital (RFH) in London.
PHE said that three out of four of her colleagues who were also brought back have now been discharged from hospital and will be kept in private accommodation where they will be monitored for any symptoms for the remainder of their incubation period.
The latest worker to be brought back was potentially exposed to the virus via a needle-stick breach of the Personal Protective Equipment (PPE) they must wear when treating patients.
“The individual was evacuated to the UK and is being admitted to the Royal Free Hospital for assessment,” a PHE spokeswoman said.
“This individual has not been diagnosed with Ebola and is not exhibiting symptoms of Ebola.”
Health officials said rapid tracing was undertaken in Sierra Leone to identify anyone who had been in recent close contact with the infected servicewoman.
A total of four military healthcare workers were identified, two of them travelling in the same RAF plane that brought her back yesterday. They were also admitted to the RFH but have both now been discharged following tests.
The two others were brought back earlier today on separate EU Medevac flights to Newcastle, and they were then taken to the city’s Royal Victoria Infirmary for monitoring in line with Ebola response plans.
One of them has since been allowed to leave.
“The three discharged individuals will reside in appropriate private accommodation and will be monitored for any symptoms for the remainder of their incubation period, in line with standard protocols,” the PHE spokeswoman added.
PHE Ebola incident lead, Dr Jenny Harries, said: “All appropriate support has, and will continue to be offered, to these six individuals. Our thoughts are with all the healthcare workers, and their families, affected at this time.
“The UK has robust, well-developed and well-tested systems for managing Ebola. All appropriate infection control procedures continue to be followed to minimise any risk of transmission.
“There remains no risk to the general public’s health and the overall risk to the UK continues to be very low.”
Sir Leonard Fenwick, chief executive of Newcastle Hospitals NHS Foundation Trust, said the two military personnel taken to the Royal Victoria Infirmary had been subjected to “exhaustive tests”.
Offering reassurance to regular patients and their families that there was no risk to them, he added: “This is a long-established infection control unit, it’s very modern, it’s well-staffed and has an international record.
“We have served the military for more than 30 years and will continue to do so and we are satisfied with our protocols and our arrangements so I can give a positive assurance that here in Newcastle, we work well with other parts of the UK including the Royal Free in London, sharing responsibility on this challenge.”