A nurse who contracted Ebola in Sierra Leone is being treated for an "unusual late complication" of the infection.
Pauline Cafferkey has been flown from Glasgow to an isolation unit at the Royal Free Hospital in Hampstead, north-west London.
She was transported in a military aircraft under supervision. People who have been in close contact with her are being monitored by Scottish health authorities as a precaution.
A statement from the Royal Free said: "We can confirm that Pauline Cafferkey was transferred from the Queen Elizabeth University Hospital in Glasgow to the Royal Free London hospital in the early hours of this morning due to an unusual late complication of her previous infection by the Ebola virus.
"She will now be treated in isolation in the hospital's high-level isolation unit under nationally agreed guidelines.
"The Ebola virus can only be transmitted by direct contact with the blood or bodily fluids of an infected person while they are symptomatic, so the risk to the general public remains low and the NHS has well-established and practised infection control procedures in place."
Professor Paul Cosford, medical director at Public Health England (PHE), said: "She was transported in a military aircraft under the supervision of experts.
"The Scottish health authorities will be following up on a small number of close contacts of Pauline's as a precaution."
Ms Cafferkey was diagnosed with Ebola in December after returning to Glasgow from Sierra Leone, via London.
She spent almost a month in an isolation unit at the Royal Free Hospital at the beginning of the year.