Pauline Cafferkey who is being treated for a late complication of Ebola is now 'critically ill'.
The Royal Free Hospital in London, where she is being treated, this afternoon revealed her condition has deteriorated.
A statement from the hospital said: 'We are sad to announce that Pauline Cafferkey's condition has deteriorated and she is now critically ill.
'She is being treated for Ebola in the high level isolation unit at the Royal Free Hospital.'
The nurse, 39, from South Lanarkshire, was admitted to an isolation unit at the Royal Free Hospital in London on Thursday night – four days after being sent home by doctors who diagnosed her with a virus.
Pauline was diagnosed with Ebola in December after returning to Glasgow from Sierra Leone via London.
She was critically ill and spent almost a month in an isolation unit at the Royal Free Hospital before being discharged in late January.
She then started working part time in mid-March as a nurse based in Blantyre Health Centre near Glasgow and had been well when she was last at work on October 1.
Two weeks ago she received a Pride of Britain award from Lenny Henry and Carol Vorderman in London and met Samantha Cameron in Downing Street the following day.
And on Monday last week she met children at Mossneuk Primary School in East Kilbride, South Lanarkshire, to speak about her charity work in Sierra Leone, where she contracted Ebola.
However, it was just hours after attending the primary school that she fell unwell and visited the out-of-hours GP clinic with Ebola symptoms.
Despite being dismissed, she took herself to the Queen Elizabeth University Hospital in Glasgow on Tuesday night where she was treated in the infectious diseases unit.