Ebola nurse Pauline Cafferkey in isolation at Royal Free Hospital

Pauline Cafferkey, who contracted Ebola in Sierra Leone, has been flown to an isolation unit at the Royal Free Hospital in London, the Department of Health has confirmed.

Greater Glasgow Health Board said the virus is present in Ms Cafferkey but said it was left over from the original infection. It is not thought to be contagious.

The 39-year-old nurse has been flown back to an isolation unit at the Royal Free.

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.

There is not yet any information about her condition, but government sources said the transfer to the specialist unit was a "highly precautionary process".

In a statement, 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."