The Health Secretary says his thoughts and prayers are with a British nurse who is critically ill with a complication from the Ebola virus.

Pauline Cafferkey, 39, was admitted to the isolation unit at the Royal Free Hospital on Friday after becoming unwell in Glasgow.

A statement from the Royal Free 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."

Ms Cafferkey, from South Lanarkshire, 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 before being discharged in late January.

Scientists agree that bodily tissues can harbour the Ebola infection months after the person appears to have fully recovered.

Health Secretary Jeremy Hunt tweeted his prayers for the nurse.

Sad to hear of deterioration in Pauline Cafferkey's condition. Thoughts & prayers with her & wonderful team looking after her @RoyalFreeNHS.

— Jeremy Hunt (@Jeremy_Hunt) October 14, 2015

Ms Cafferkey contracted Ebola while working as a nurse at the Save the Children treatment centre in Kerry Town.

A report from the charity in February said she was probably infected as a result of using a visor to protect her face rather than goggles.

It said she was unable to use the standard protective goggles because she could not get them to fit properly.